He's never been a fan of the no trinity. We did a few dungeons together and he didn't like any of them (he usually enjoys dungeon running). He also loves healing and while it's somewhat possible to do in GW2 it's not in the way he prefers. I also know he hates the limited skill sets in GW2.
Other than that, he seemed bored with the game 'progression'. I dragged him around to do map completion and he acted like it was a chore. Each map was a check list of essentially the same activities, I guess. Maybe if combat had been more varied he wouldn't have noticed as much since he usually likes senseless killing. I also get the impression he feels like he 'finished' the game (re: map completion), which as someone who doesn't like the dungeons and doesn't PvP would make sense. Nothing in LS has interested him at all, even his enthusiasm for SAB was over after he'd gone through it once.