>>35578285The Pokemon selection (in BW anyway, BW2 was one of the best in the series in this regard) was a huge step down from previous games. I'm not too bothered about the fact that you can only use new Pokemon, I found it refreshing in some regards even though I always use new Pokemon in my first playthrough of any gen. What did annoy me is that there were only about 150 Pokemon to choose from. What this meant was that even though the Pokemon you saw were new at first, every trainer used the same ones and it got tiresome by the end of the game. The first time you see a Woobat instead of a Zubat is nice, but by the end of the game you're sick of them. Compare this to a game like XY, where Zubat only appears in one cave in the game. This was possible because they had a much larger Pokedex. The relatively limited Pokedex also makes replayability worse, since there are less different Pokemon to use on a new playthrough.
And while gen 5 did introduce some QOL changes (like every generation before it), it didn't do a lot new mechanically. Gen 2 added weather, hold items, breeding. Gen 3 added abilities, natures, a vastly improved PC storage system. Gen 4 added the physical/special split and Wi-Fi battling. Gen 5 didn't add anything as significant as any of those things.
I don't hate gen 5 and I definitely wouldn't say it's the worst, I think that honour goes to gen 7. But out of the first 5 generations it's definitely my least favourite. I don't get why people get so offended when you say you don't like gen 5.