Activison have made some awesome games but I've also heard bad stuff about them.
A TNA game would be awesome but they need to think outside the box. Focus on things like the Ultimate X, I remember I saw a game review for the midway game and they said although the game was really lackluster with some work ultimate x alone could be a WWE beater. So I think they need to work on being different and innovative. I'd suggest trying to make the game more fast paced than WWE's. Focusing on waepons and a hardcore style could work too. A big game changer could be strategy, making their enemy IQ better than WWE's (which has never been great) the WWE games are fun but you've never had to strategies against your opponent so if Activison could find a way to do that they would offer something never seen before.
Any company that picks up a TNA game is in store for a challenge though. In 2009 WWE's games were getting repetitive and dull, so it didn't take much to be able to compete a wrestling game that wasn't WWE's was enough really. In 2012 THQ stepped up their game though and reinvented the franchise with WWE 12 which was the best wrestling game since N64's No Mercy and perhaps better than that. WWE 13 (aside from glitches) is even better, if WWE games keep going this way no one will care about a game from a smaller company because the WWE's game won't just be bigger it will most likely be better too. There's no room to get lazy and produce a generic TNA game, because even with a great game you've got tough competition.