Which changes would you do in any of Ash's teams?

[Sakuraa]

I'm fine with most of Ash's teams. Most of my changes are minor.

Kanto- I probably would have not had him catch Krabby, Muk, Tauros, Lapras, or Primape. They really have never amounted to much. The rest of his team is fine. I would prefer if he didn't release Pidgeot because it never seemed necessary to me, and Snorlax could have just been added to his team after Butterfree's departure.

Sinnoh- Just my personal preference, I would have loved to see Ash with Chatot instead of Staraptor. I just love that parrot. I also would have left off Gible and just kept Gliscor. I never understood the point of adding Gible at the tail end of the series. Ash opted for Gliscor over Gible for the battle against Paul anyway, so...yeah. I might have evolved Buizel.

Unova-I'd make a lot of changes here. Much smaller team. Actually, I think I could make two teams for him. First version, he captures only the three starters, Krookodile and Boldore. No need for Leavanny since he had Snivy, no need for Scraggy since he'd have Krookodile (not that either were really utilized as dark types but still), and no need for Palpitoad with Oshawott. Unfezant was treated like crap anyway so, she can go.
2nd team option would be just Pignite, Leavanny, Palpitoad, Boldore, and Unfezant (treated properly) as captures. Instead of having all starters, he can take just Pignite and use the non-starter grass and water types he had (Snivy and Oshawott can go to Cilan and Iris respectively). Since Palpitoad is also ground-type, Krookodile can be replaced here. Scraggy is again unnecessary here since he only knew fighting-type moves (and headbutt) which Pignite covers, so he's still out. Honestly I never cared for Scraggy, so I don't mind removing him.

Kalos-Eh. I personally would not have given him Noivern. There's nothing he really added that Talonflame, Hawlucha, or Goodra couldn't do imo, plus he was captured super late. As for what would replace him, I could see a lot of additions actually. I personally like that he didn't have a grass-type here, so I think some other options could work. A male Meowstic, a fairy-type like Swirlix, or Aurorus even. If I had to pick one, I'd probably add Meowstic. Aurorus doesn't really add anything in terms of coverage, and Slurpuff was used by Sawyer so I'm hesitant to give Ash Swirlix.

Alola- I hated Ash's team here, so I'm doing a lot of changes. If Rowlet wasn't made annoying as f*ck, Ash can keep it. Otherwise, I'd replace it with Pikipek. Torracat would not evolve. Replace rock mutt with Mudsdale and add Passimian and Hakamo-o in place of Naganadel and Melmetal. I always thought Passimian looked good with Ash and never liked him getting mythicals and ultra beasts, but I'm fine with a Psuedo-legendary. He'd have two fighting-types, yeah, but they could just not give Hakamo-o any fighting moves. Or make one physical and the other a special attacker.

Journeys- Tbh, if it were up to me, Journeys would not exist and Ash would take a proper journey through Galar doing the gym challenge. His captures would be Intelleon, Corvinkight, Flapple, Sirfetch'd, and Dracovish.

So tldr
Kanto-Pikachu, Squirtle, Bulbasaur, Charizard, Pidgeot, Snorlax.
Johto- Same
Hoenn-Same
Sinnoh- Same but replace Staraptor with Chatot and no Gible.
Unova- Team 1: Pikachu, Oshawott, Pignite, Snivy, Krookodile, Boldore. Team 2: Pikachu, Pignite, Palpitoad, Leavanny, Unfezant, Boldore.
Kalos- Same but replace Noivern with Meowstic.
Alola- Pikachu, Rowlet/Toucannon, Torracat, Mudsdale, Passimian, Hakamo-o
Galar- Pikachu, Intelleon, Corviknight, Flapple, Sirfetch'd, Dracovish

 

[Enzo]

I do agree with @Sakuraa over Gibble. I don't think Gibble was a bad Pokémon, and was actually pretty competent, but it's just a Pokémon that got captured so late into Ash's Sinnoh run that it almost feels pointless. While I do like the idea of Gliscor being part of the team full time and not being sent away for training with someone else, I do think I could get behind it if they used the extra time available for the scorpion-bat to be temporarily out of the team and with Gibble not existing if they used this time window to actually train Torterra.

I don't mean in the sense of putting the blame for Torterra's botched storyline on the dragon, no, far from it. But I just feel that we could've had more out of Torterra if it wasn't on the team, you know?

And honestly? Buizel deserved to evolve. This Pokémon did so much for Ash and, to this day, still feels like one of the Pokémon who deserved to evolve the most out of every other mon on the main cast.

So my Sinnoh revamped team would be:

Pikachu
Staraptor
Torterra
Floatzel
Gliscor
Infernape

 

[Audino1008]

I'd like to expand on my choices a bit...
I like a lot of the ideas that were in this thread but I think it would be kinda complex to make them perfect in my eyes, and I don't want Ash to catch any Gen 8 Pokemon (give them to Goh, Ash could represent all the other regions)

So, Journeys starts off with Ash having Pikachu, Charizard and Bulbasaur on his team. They kinda join his team off-screen before Journeys start. They are then slowly faded out of his main Team as he catches more Pokemon, but they can still stay at Cerise Lab.
I like the idea of Ash having one Pokemon per Generation. So...
Pikachu
Tyranitar
Flygon
Lucario
Volcarona (Shiny?)
Greninja
Solgaleo

I think it's good representation for each region, but I still really want to keep Dragonite and Gengar, and maybe add Rhydon too, but I don't know how... I don't want him to have too big of a team. So maybe they can mostly stay in Cerise Lab alongside Bulbasaur and Charizard? Dragonite especially is my favorite of all of Ash's Pokemon ever. And I still want to have them battle... Ugh, I'm at a pickle here. I don't want another BW situation but I want to keep Dragon boi...

One more thing, Lucario would be often seen outside of its Pokeball, even after evolving.

Anyway, with Ash representing Gens 1-7, we can have Goh representing Gen 8.

His main Team would consist of...
Cinderace (stays outside its Pokeball even after evolving, alongside Grookey)
Inteleon
Grookey
Single-Strike Urshifu

And then some of his other major Team members could be Corviknight, Toxtricity, Falinks and Morpeku (I have other plans for Team Rocket).

And for Team Rocket, I'd have James catch a (Shiny?) Gible and Jessie catch a Shinx, and maybe they'll evolve but only once.

 

[Ghost Diplocaulus]

As per my recent changes to Ash's Companions' Pokemon teams, I decided to revamp Ash's captures as well. Unlike the companions, my versions of Ash's teams don't have as many changes, but still enough to warrant some explanations and elaboration.

Spoiler: Kanto

• Pikachu
• Spearow-->Fearow
• Caterpie-->Metapod-->Butterfree
• Bulbasaur
• Charmander-->Charmeleon-->Charizard
• Squirtle
• Tauros

I decided to swap Ash's bird capture from Pidgeotto to Spearow, and yes, it'd be the very same Spearow that led the flock attack against him and Pikachu. In my version, after Pikachu defeats the flock with Thundershock and Ash gets ready to take him to the Pokemon Center, he notices that the lead Spearow is lying unconscious on the ground, to injured to keep up with its flock. Ash is angry at being attacked, but doesn't have it in him to leave the bird in that state, so he decides to catch it so it to be healed too. I just feel this setup has way more potential character development for both Ash and Spearow/Fearow, and contrast with Charizard's arc in that Spearow was initially antagonistic only to become fiercely loyal (in no small part out of gratitude for Ash helping it) while Charizard was originally friendly only to become disobedient. Spearow/Fearow would also get to participate in more battles and even the League, and instead of being released would simply stay at Oak's Lab prior to the Orange Island's arc as per the Professor's request, as it would turn out the Flying-type Pokemon at the Lab need a leader.

Butterfree still plays the same canon role of being Ash's first release, but I'd have him have a bigger battle presence so that said release has more emotional impact.

The Kanto Starters stay exactly the same.

Tauros would be a single capture as opposed to an entire herd and would get to be used in some Gyms as well as the Pokemon League.

I decided to get rid of Kingler, Muk, and Primeape simply because they feel like the most superfluous of the Kanto captures and really only kinda take up space unnecessarily, so... yeah, sorry guys XD.

Spoiler: Orange Islands

• Pikachu
• Bulbasaur-->Ivysaur
• Charizard
• Squirtle
• Lapras
• Snorlax

Because I'm just really into the idea of Ash's Kanto Starters matching Red/Leaf's Smash Bros. setup, I'd have Bulbasaur evolve during the Orange Islands saga. Lapras would still be released, but like Butterfree would have its role expanded so that it has more feats than just tying with Drake's Gengar, though this would require revamping at least some of the OI Gym Challenges. Snorlax also gets to participate in the battle against Drake, since Tauros already got time to shine at the Kanto League in this version.

Spoiler: Johto

• Pikachu
• Heracross
• Chikorita-->Bayleef
• Cyndaquil-->Quilava-->Typhlosion
• Totodile-->Croconaw
• Egg-->Eevee-->Espeon

Yeah, the Johto team stays the same as my original version, with Heracross being a permanent mainstay, Totodile evolving since I feel Croconaw still looks goofy enough to serve as comic relief, and Espeon being the one to promote the Johto breeding mechanic via hatching from an Egg as an Eevee. In my version, Ash would get the Eevee Egg from the Kimono Girls (Sakura's Espeon is already at that stage by the time of her debut), who'd be the ones to host the race where Ash originally won his Phanpy Egg (though this would of course have to take place much, much earlier). Espeon would then go on to become a rival to Gary's Umbreon (Eevee/Espeon would look up to Pikachu as a big brother and is personally insulted that Umbreon beat him), constantly battling it and losing until the Ash vs Gary match at the League, where Espeon finally gets to win.

I should also note that Cyndaquil only reaches the Quilava stage during Johto, the fight against Jasmine's Steelix being the point where it evolves, and then becoming a Typhlosion in DPP.

Spoiler: Hoenn

• Pikachu
• Taillow-->Swellow
• Treecko-->Grovyle-->Sceptile
• Trapinch-->Vibrava-->Flygon
• Torkoal
• Absol

Also still the same as my original version for Ash's Hoenn team. I know keeping Torkoal might seem weird, but I have no problems with it, it just needed to have a better battle record which is not actually that hard to fix. Flygon is 110% bias because it's one of my favorites, so I've always wanted Ash to have one, while Absol is just because I feel like Ash would befriend one of these things easily, and it'd be really cool as his first official Dark-type.

Spoiler: Sinnoh

• Pikachu
• Starly-->Staravia-->Staraptor
• Turtwig-->Grotle-->Torterra
• Buizel
• Chimchar-->Monferno-->Infernape
• Snorunt-->Froslass

Due to May being the one to catch Aipom in my version, Ash would catch Buizel from the get-go instead of trading him. I also decided to move the Snorunt capture to Sinnoh instead of having it happen in Hoenn, mainly so that Ash doesn't have to leave any of his Hoenn mons at Oak's during BF to make room. Because Ash has Froslass now, Paul would use Gliscor as part of his Sinnoh League team in the match against Ash. Torterra still gets to actually master the tanking battle style because it deserved to have that bone throw.

Spoiler: Unova

• Pikachu
• Pidove-->Tranquill-->Unfezant
• Oshawott-->Dewott-->Hisuian Samurott
• Snivy-->Servine-->Serperior
• Egg-->Mienfoo-->Mienshao
• Krokorok-->Krookodile

Unova gets a heavier revamp than the rest. I decided to remove Braviary and put Unfezant back and make her a better battler when compared to her canon version, which is much easier to do now that there's no messy rotation. If this seems like an insane decision, well... I have plans for Braviary.

I decided to only evolve Oshawott once during the Unova saga because I decided it'd be neat if Ash recalled Dewott to his team during Journeys' Legends Arceus saga and evolve him into Hisuian Samurott.

Snivy gets promoted to full on ace and evolves all the way into Serperior. To acomodate this, Trip's starter would be a Tepig instead and would become an Emboar. Meanwhile Bianca would get Samurott and Cameron would just not use any Starters (though he'd still use a proper full team against Ash).

Mienfoo plays the same role as Scraggy and would evolve alongside Cameron's Riolu at the League, with both Pokemon being the last ones standing on their respective sides.

Krokorok is captured eariler so that he can get a few more battles, but is otherwise unchanged from canon.

Spoiler: Kalos

• Pikachu
• Froakie-->Frogadier-->Greninja
• Fletchling-->Fletchinder-->Talonflame
• Hawlucha
• Goomy-->Sliggoo-->Goodra
• Swirlix-->Slurpuff (Shiny)

I decided that instead of Trevenant, Ash would get a Slurpuff so that he can have a proper Fairy-type catch. Fun fact, this way Ash has at least one Pokemon of every type. I also made Slurpuff a Shiny because people are unreasonably icky about Ash catching something pink, but Shiny Slurpuff is not pink, so problem solved. To avoid species overlap, Sawyer would use an Aromatisse.

Goodra doesn't get released and its evolution is more spread out. Everyone else is the same as canon.

Spoiler: Alola

• Pikachu
• Rowlet
• Rockruff-->Dusk Lycanroc
• Litten-->Torracat-->Incineroar
• Poipole-->Naganadel
• Meltan-->Melmetal

I still don't think the Alola team needs any changes, so it's still the only team to match the canon one exactly. The only real change is that I'd have Poipole participate in some official battles prior its departure so that its comeback as a Naganadel feels less jarring.

Spoiler: Journeys

• Pikachu
• Grookey-->Thwackey-->Rillaboom
• Egg-->Riolu-->Lucario
• Galarian Farfetch'd-->Sirfetch'd
• Dracovish
• Hisuian Braviary

Something something, Ash should have gotten Grookey, something. Something something, Gigantamax Rillaboom, something. Anyway, this is what I'd save Braviary for: I decided to have Ash catch a Hisuian Braviary because why not. It's a cool Pokemon. Also, I feel like saving the more powerful/fully evolved captures for the later parts of Journeys would have worked better.