I've seen this go both directions and I agree something is definitely up. Sometimes at late nights (Or Aussie time in my case) you will see DPS needed in trial roulette. It can then go either way, my melee friend can get instant que and my bard/blm wait 20+ mins, or I can get instant que and melee friend is waiting 20+ mins etc.

Its pretty annoying either way to see it demanding DPS and you join up and wait as long or longer than usual.