Let's face it. Tristan has dueled with his OWN deck like what? Once I'm pretty sure in the entire anime? He lost that one against the Big Five, then he dueled AS the Big Five and lost THAT one too? He barely duels and the only reason's he's really there is so that he can be a cheerleader.
I'm surprised he wasn't in the starting roster. He ran a machine deck in the anime with the Robo series as his ace. So I guess we're getting generic Machine and Warrior support.
Well, probably most of the cards we will get from him will be trash, so I don't even know why people are so eager to have him in the game. They could add other chars period even though Tristan is a main character or not.