why isn't trigon a justice league villain?

trigon is uber powerful and dangerous enough to give them serious trouble; and,although he has a personal history with the titans that's all retconned with the new 52.I think he should be a justice league villain.

Because none of the regular/primary members besides Zatanna and the fates really have any magical ties or anything really to do with Trigon type stuff.

Trigon as a character is connected to Raven, who is a Titans character. Its what he is meant for.

trigon is raven's father and unless raven became a justice league member, he remains in teen titans