I can agree with the algorithm needing work on some roulettes. Some of the others seems to always default to one even if everyone already did it.
Level 90 roulette - Dead Ends. Almost without fail.
Leveling Roulette - For me, Ghimlyt Dark and Kugane Castle popped up a lot compared to others. If it was the more recent ones, it was almost always Vanaspati.