I've been doing daily roulettes for a few weeks now. In my experience, as a healer..

Low level roulette usually goes fairly quick. Main scenario roulette often takes 15+ minutes, even shortly after reset on weekends. High roulette, I queue with a DPS and we usually get instant, or at most, 5 minute wait.

I don't have trial roulette unlocked, but trying to queue for the trials we still need often leads to 30 minute or longer waits at primer playing times - if we're in the off hours, we won't even get a single DPS joining.

High I think is fine, but main scenario/trial could use some more incentives..