OK, backwards I guess but,
Dislikes:
1. badly coded anything - character / stage / whatever... (bad coding that causes crashing or hang ups or lags in gameplay)
2. Overpowered (I like a match to last more than 5 moves or 5 seconds)
3. AI, Only needed to possibly keep a character from going into a 'penalty' state if computer controlled or activating a short range attack when an opponent is out of range. Any well developed character should be balanced enough not to require much of an AI. I like to see a variety of different moves when computer controlled, not a repetition of the same overpowered and overdamaging moves.
4. Infinites, infinites, infinites... (able to do a move over and over again causing damage without rest).
5. Comboholics. Too many combos leads to #4 again doesn't it?
Likes:
1. Originality - something different
2. Balanced. Able to be played as as well as played against which leads into #3...
3. Has none of the dislikes...