With online play this could be everything Soul Calibur wasn’t. Biggest excitement for me since King of Fighters 98 was announced for XBLA. 
Call me when they get STHD released. Marvel is cool because it brings a lot of hype to the fighting game community, but it’s a pretty bad game.
Is this the one where people who don’t know how to play just spam Cable?
Don’t forget about the people who DO know how to play that spam Cable.
Isn’t this pretty much the most popular 2d fighting game?
It’s got the rowdiest players, but no - 3S and ST are the most popular fighting games. 3S gets the highest turnout at all the big tourneys, and ST still has several ST-only tourneys in Japan. Opposed to that, MvC2, while still popular here, hasn’t evolved (no really new tactics in years, same few top players dominate the game), and they don’t even play it in Japan. So, no; MvC2 is far from the most popular fighting game.
The general (gaming) public may like MvC2 the best. I don’t know. It was popular with less serious fighting-gamers back when it came out. That’s what could be meant by it being the most popular, SG.
Then again, I think it came out long enough ago that the casual fighters don’t really care about it any more, so it’s no longer the most popular.