I would say that the current crop of fighting games have been more of an evolution then a revolution, but after VF4, what more can you add? Obviously you expect graphics to improve, and more characters, moves, environments to be added, but those are just part of the evolution of fighting games. Online play is the same. To make a revolution, at this point, would require a shift in the way we play fighting games.
For instance, for years, most boxing games were played the same way, at least with the same basic concepts. But when EA created Fight Night, they created a new style of control for a boxing game. Not sure I'd call it a revolution, but at least they were trying to do something new and different with the way we controlled our fighters.
KFJ