I'd like to see a fighting game all goofy, with attacks that make you go WTF and laugh at the same time, with funky characters, and all sprinkled with neat and dynamic animations.
Screw serious ones, there are too many around already.
I think, perhaps, you're looking for something like this:
Slap Happy Rhythm Busters ?
It's a decent fighter with a theme similar to Jet Set Radio's. It's hella expensive if you're hoping to get it legally, however...
Personally, I'm really tired of seeing fighting games progressing (or digressing?) to a point where first hit = win. By that, I'm referring to combofests, with the recent Hokuto no Ken fighter being a very blatant example of this. I guess a good thing the game managed to do was reflect the insanity of the anime and manga series well enough, at least. Don't get me wrong, I love combos, and I love trying to find broken ones, at that. The problem is that there comes a point where it's just too much and it ruins the competitive aspect of a fighter. I'm with the others in favor of a 'down to Earth' fighter. I think it'd be interesting to see something that completely realistically simulates a fight, even more so than Virtua Fighter.