I agree with all four or those! I wish that Black/White 2 would have in some way have connected more to your previous adventure. I wish that oyu could have battled your former self, and could have some way associated with the gym leaders that were in Black/White for help. Team Plasma was the same, but still.
This isn't a big dissapointment for me, but yeah more customization would have been nice. It would be cool to change the skin on your pokedex and your outfit. That wouldn't be that hard of a feature to add, and I wish that Gamefreak had done that.
I think that allowing a trainer to swim would be dumb. If your trainer is swimming, then where would they put their bags and Pokeball and things? I think that having a trainer to swim would mess up the HM system as well.
Yeah, I never thought about or noticed this, but it is disappointing.
Changes I think that should've happened to improve the game:
More interaction with the media. Although I liked that you could watch Tv and they had announcements on places that you can go to catch wild Pokemon, I wish that there would be announcements to places where you could go to experience new festivals. Also, aybe there could be a weekly, daily, or even monthly magazine that would say what's going on in the Pokemon world and would change your adventure. I think that would be cool as well.
More interaction with holidays. I wish that you could find a rare Pokemon on holidays, or that there were special items that you could receive on holidays. Kind of like Animal Crossing.
More to do with memory link! It was a cool idea for GameFreak to add a Memory Link feature to Black/White 2, but I wish there had been more that you could see and more that you could do! It's cool to be able to battle Cheren and Bianca and all, but you still don't really understand everything that happened between Black/White and Black/White 2. I just wish Gamefreak would have added more.
DLC. DLC such as new trainers costumes and pokemon costumes would be nice, even if for a monetary fee. More memory links sequences via DLC would provide much profit to Gamefreak as well.