Well I stand corrected. All I saw everywhere was the initial 4-character trailer that was released a couple of days ago. I think it's cool that we're getting the Adventure characters' Megas in a fighter, but man... just the idea of a 12 character roster is extremely limiting for a giant (character-wise) franchise like this, but to pick almost exclusively from one series (and all "heroes" to boot) is a bit disappointing. I'm still excited, just a bit less so.
Shoot, I hope the Megas aren't separate characters as well in that case, like they were in the original. If that were the case we know the entire roster already!
EDIT: Never mind, somehow forgot about Gatomon and Gomamon