I, as one of the players who already got the roulette achievement would say that the Mentor Roulette is working fine as it is considering that filling up almost every duties in this game itself including extreme primals could be considered as mentoring.
I also still run Mentor Roulette for the sake of the "roulette" despite already got the mount, but that's just me and I couldnt vouch for any others.

Quote Originally Posted by Legion88 View Post
Mentor Roulette is not a Roulette to help new people... it's just a filler roulette for more or less every damn duty in DF available.
It dosn't include an algorithm for filtering dungeons so you get into one with a new guy. It just places you into the next fitting queue for any dungeon.
Actually, there was one occasion when I queued up for Mentor Roulette and it didn't pop for more than 2 hours, I even withdrew and requeued thinking that it may be broken, but after the duty actually popped, it placed me into Sycrus Tower. So i would say that there is algorithm that take priority to match players with duties with new players or duties such as the 24 players raid that requires a lot of players to fill in altho not exclusive to it.