If Pokémon Time is supposed to be a retrospective look at older generations, featuring Gen IV would make me feel nothing special. It still feels fresh and new to me, and will probably feel so for years to come -- only recently did I gain an appreciation to Gen III's time. I guess that's to be expected from older fans, since we don't pay as much attention as we did back in the day, but I feel that this Pokémon Time thing is probably headed more to fans that appreciate the old times.
Either way, if anything, the Kanto games are the oldest ones currently, since Emerald released after FRLG. A bit older is Colosseum, although XD (which is to Col pretty much what B2W2 is to BW) is more recent. I'm still absolutely for the eShop port suggestion for the RSE anniversary, although I don't know how much viable it is... I mean, even a port would get a lot of exposure, and it's unlikely that 2013 won't bring a completely new game. Will fans accept B2W2, an RSE port in 2012 and a new game in 2013? Knowing the fandom, I won't say this is impossible, but I wouldn't be too sure. Maybe the port is more likely after Gen VI debuts.
Either way, if anything, the Kanto games are the oldest ones currently, since Emerald released after FRLG. A bit older is Colosseum, although XD (which is to Col pretty much what B2W2 is to BW) is more recent. I'm still absolutely for the eShop port suggestion for the RSE anniversary, although I don't know how much viable it is... I mean, even a port would get a lot of exposure, and it's unlikely that 2013 won't bring a completely new game. Will fans accept B2W2, an RSE port in 2012 and a new game in 2013? Knowing the fandom, I won't say this is impossible, but I wouldn't be too sure. Maybe the port is more likely after Gen VI debuts.