They're not weakest. You just don't see them because they need better PR. Hunters are the title characters. Everyone want to play the title character. Warlocks can fling space magic nukes around so people want to play them. The only thing Titans have going for them is the armor but even then that's not widely publicized. Titans just lack popularity because they aren't showcased as much. So people don't play them as much as the other two. As for my Striker Titan? I'm not the greatest Crucible player ether. I have my good days and I have my bad days. I don't feel weaker or stronger then ether of the other classes.