You are basing your statement off of personal preference. The XP you gain in a leveling dungeon from killing the monsters isn't significantly different than what you could make via other means in the time that you save. Of course, this is moot since it seems that the quicker grind is to queue for your daily leveling roulette, then queue for your daily trial roulette, then queue for your daily main scenario roulette, then queue for your daily guildhest. An hour well spent (with a tank queue, anyway)