Not sure if this is the spot to post this, and sorry if this idea has been brought up before, but I'm really intrigued by the tag battle mode in this game. So I'm hoping that this mode will popular in tournaments.
2 vs 2 can bring an interesting team strategy to the game. I'm sure if two friends who always practice together were to fight two players who were just randomly thrown together as a team, the friends would have an advantage, since they would have specific strategies and ways of working together to get the win.
Now the problem with such a tournament format would probably be attendance, since not everyone would want to have a partner to climb (or drag) their way to victory with. So to deal with this I would suggest allowing people to enter the tag tournaments alone (and have control of two characters when they play), but they would have to pay double the entry fee than what two players on a team would. So if it's a $20 entry fee to get in the tag tournament, a single player would have to pay the full $20, while 2 people on a team would just pay $10 each. This would add incentive for people to team up with someone.
Anyways most of my tournament experience is with the Soul Calibur series, so I've never been to the other fighting game tournaments that featured tag modes (TTT, DOA etc), so my apologies if this idea is nothing new.