AutoSaver, you just have to put everything into the perspective of the year something came out. If you look at it the way I described you would be impressed, but if you look at it only for being the start of Iizuka ruining everything then of course you will have a mixed opinion on it. I am not telling you to love Sonic Adventure, but you should at least appreciate the work put into it, the era it came out in and not say every other persons opinions are just plain wrong.
As for the characters, I do not mind dozens of characters, but the issue was that you HAD to play as them when most people just bought the game for Sonic.
Something I would have loved is in Unleashed if you could meet up with some random characters like Vector, Cream or Rouge (anyone would do, I guess) who are on a vacation or something, instead of getting missions from random human characters we will never see again. That would have helped it feel more like a Sonic game at all, too.