They should have no trouble getting gabe Logan, Sony owns the freaken IP. They also own the developers that made the game!
All it should take to get him is probably like 3 signatures (obviously I know it will take more but still c'mon it won't take nearly as much as some of the other characters). and yes I understand that popularity plays a role, I hate to bring up Nintendo but they truly understand how these types of games work. They don't see what character is popular or has a game coming out to get them a "spot", NO!
They jam as many characters as they can into it and just let whatever happens happen (that's why we have a new kid icarus game) and nobody asked for the ice climbers or game and watch. I love you Sony but you went about this all wrong, it isn't about having a crossover fighter, it's about celebrating the history. Reviving old friends and having a great time.