I've read a few posts that state the character roster won't be that much bigger than Brawl's.
But take it with a grain of salt.
If they're playing with tournament rules, it just means they're not fond of random elements that ruin an otherwise competitive match. I'm the same.
My brother and I took Brawl pretty seriously. We were only two, so we had a lot of 1-on-1 sparring matches.
We ended up as probably 2 of the top 5 players in this country, but we got bored eventually. Brother moved over to MvC3 and now he's dominating local tournaments with ease. He's a pretty competitive guy.