Hmm, there isn't really too much I dislike so far, at least in terms of maps and conditions. I'd say character wise, for Golden Deer, Lysithea is my least favorite in that house mainly for her personality. Don't have any least favorite for Blue Lions students though. I also dislike that some paralogue battles are pretty easy to miss, especially if it's with students not from your chosen house, or they're ones you don't want to recruit, which in turn can make it to where you miss the deadline for certain supports; it's easier now on my second playthrough after I figured it out, but still was kinda frustrating for the first time lol. And, while I don't really dislike it, but after the timeskip there really isn't much incentive to spend your free time roaming the monastery; unless you're curious about what the characters have to say for the current month's mission or if you're still trying to raise certain supports, but otherwise eating, cooking, fishing, etc. becomes kind of pointless outside of the few quests you'll still get. Of course, some things might change after I complete all four routes. For all I know there could be maps and conditions later in the Blue Lions route, or the Black Eagles route's for either/both Edelgard's and the Church's paths I might dislike.