Yeah, the majority of those plots are terrible. Suggesting straight-to-video Disney movies for KH plot? Shame on you. Might as well have suggested an eye doctor world for Alladin 4: Jafar May Need Glasses.
My main worry about this game is the heartless bosses. I've generally disliked Heartless boss fights, and this game probably won't be an exception. The mass HP of annoying boss fights is what worries me further, but otherwise there isn't much to gripe about. Every KH had its own criticism before and after it came out.
Public Opinion:
Kingdom Hearts 1: Final Fantasy + Disney? FAIL.
Chain of Memories: Horrible graphics and annoying gameplay. FAIL.
Kingdom Hearts II: FAIL.
Re: Chain of Memories: Overlooked by KH2 Final Mix, though the US release received from panic criticism at first from the voice actors.
Yet in the end:
Kingdom Hearts 1: Possibly the most respected in the series in terms of story and gameplay together.
Chain of Memories: The most respected in the series in terms of story alone.
Kingdom Hearts II: Received criticism, but after Final Mix was released, it was easily the best Final Mix KH
had and opened the door BBS, aside from being an awesome game overall.
Re: Chain of Memories: The voice actor epidemic was quickly overturned and became respected.
358/2 Days doesn't seem like it will be the first in the series to break this chain, as it was stated each of the three games will become connected in KH3, whether we're overlooking something or not. Even if it's not, despite the game being made for multiplayer in general, I doubt it will give off the "regrettable" feeling after playing it, especially since it's not even released in the US yet.