>>41229266More serious tone, some questionable choices with graphics, no old Pokémon until post game, and the handholdery+heavier emphasis on story start in this gen. I think the point that affected sales the most was the "no old Pokémon until post game" part.
That said, I like bw quite a bit. It had a great region, a well crafted plot for pokémon standards, and I did like the restriction to new mons only. I wish that became a staple, actually, because I love to try what the new gen has to offer in terms of creatures. But it looks like the average Pokémon player wants pikachu and zard for every fucking team.
Maybe a thing I disliked were the copypasted legendaries: thundurus/tornadus/landorus and the four swords of justice were kinda redundant. But that was a trend that had started with gen 4... Too much legendary bloat, seriously