One of the interesting things Capcom vs. SNK did was incorporate both playstyles together, into one game. Actually, it had more than "both." While it wouldn't be the same, really, I'd imagine Capcom would come up with a way of catering to Smash Bros. fanbase with a similar control/attack set-up. Still, it would be a traditional fighter with non-traditional controls, but it wouldn't be a bad thing for many people.
I'd buy it. I'm going to go buy this, in a few minutes.