Are you serious or are you just trolling here? Just in case you really mean this, let me remind you that not only BW is hated by fans, as Nekaku already mentioned, but many had (and some still have) dislike for Johto as well.
In Kanto, Ash was unskilled trainer who got his first two badges without winning them. But then, he got more confident and won legally the other badges and made it on decent place in his first Pokémon League Tournament. Then he beat Orange Crew as well, which is something too. In Johto, they decided he was too strong and toned down his Pokémon roster significantly. Honestly, the only decent Pokémon he had were Bayleaf and Noctowl and in the end, it was his Kanto team that battled most of his matches in Johto League Tournament. On top of that, Misty and Brock had nothing much to do in that series. So, they decided to change things in Hoenn and Sinnoh. True, they still regressed his team with letting him start with just Pikachu, but Ash himself was no more novice, that tittle got to May and Dawn respectively. However, in BW, they not only regressed his team with only Pikachu, but they also regressed Ash himself to a novice, pretty much throwing all of his small character development away. And on top of that, the new cast had nothing much to do, just like in Johto. They pretty much mixed the wost of Kanto and Johto, with nothing good from them getting to the mix. I am really glad they did not do that in XY.