The problem(s) with low level roulette (or any specific roulette) is that that's not necessarily where any particular subset of players are when another subset "needs" them. If someone new to Ifrit HM is stuck waiting in queue, while loads of experienced players are grinding through Haukke HM or Sastasha SM together (again), that kinda sucks.

Throwing every possible duty into one roulette cuts down on that problem a good deal. Mostly cuts down on new players waiting for experienced players to join the specific roulette they need.

And to cut down on possible trolls, I still like the idea of giving the new player a pop-up asking if the party was helpful; if yes, bonus tomes, if no, fewer (or no) tomes.