
An instantly identifiable cast of characters. It's instantly obvious what the role of each character is, just by looking at their size/stature.
you picked an old pic that doesn't have the designs that were actually on the release game. Also the poses aren't as good.

I think TF2 illustrates the thing some of you guys were getting at re: fighting game character designs. TF2 is not a fighting game per se, but like them, it doesn't have a lot of in-game narrative. I had no idea, for instance, that
Mortal Kombat or
Street Fighter even had a plots until about five years ago. So a player, especially a new player, must determine which character will fit their playstyle just by looking at them.
TF2 characters are well-designed because you can tell by looking at each what their relative speed will be, which is going to have the most health, the primary function of each class, and the level of and type of skill needed to successfully use their weaponry (at least before they started adding more weapons with advantages and detriments). They also read well in-game, where there's shit flying around everywhere and there could be up to 32 players at once.
I don't agree at all the fighting games
have the best character designs, but I do think fighting games require better, more communicative ones.