I didn't really hate that part... It was more that the characters were completely alone which made the game feel very cold and isolating, for some reason, exacerbated by how cold and stiff the majority of the characters were. 3D would be the same if not for the Dream Eaters + Riku and Sora being superior characters overall for me. Also, I hated the Command Deck. 3D also features the command deck, but I enjoy flowmotion and links, which offsets my annoyance with the deck's return. Plus, just filling the deck out with Balloons and Cure spells meant I could ignore it for the most part.
A nice idea that I've read suggested before--I think it's unlikely to ever happen, which is a shame because I'd love it--is that they make a game where you have three scenarios like BbS again, except, instead of playing as one character solo, you play as a team (maybe with one leader and two party members, or the ability to alternate). One scenario is Team RAXI, one is Team ATV, one is Team SRK (possibly with MDG or some combination of the six as options). That's the best way to actually utilize an enormous cast of characters, if they plan to keep them around. I think the main reason that would never happen is because BbS was really a case of all three characters going through the same worlds... Whereas a game of teams would require four or five individual worlds to be built for each scenario. Even if they all went to the same first and last original worlds (with say four unique Disney worlds inbetween), that would be around 14 levels, and KH3 shows us the most they can hit is eight or nine--and that's with the original worlds being completely crap at the same time, which I'd like not to be repeated going forward.