Remove Praetorium

[Astrahime]

Prae has nice rewards in tomes (poetics and event mogtomes), it also gives a big chunk of XP if you are leveling.

All of this is supposed to incentivize people to do it in order to help out new players. However, this has backfired and less than a third of the runs you get actually have someone who's doing it for the first time.
MSQ roulette had its place back when Duty Support didn't exist, but it exists now so the "let's help new players finish the seventh umbral era" reason doesn't hold merit anymore.
Also, "not a lot of roulettes"? You've got Level 50 dungeons, Levelling, Trials, and Alliance Raids. The only one you're missing is Normal Raids.

[Nicola_Kunu]

All of this is supposed to incentivize people to do it in order to help out new players. However, this has backfired and less than a third of the runs you get actually have someone who's doing it for the first time.

So it is still working and hasn't backfired - 1 in 3 runs is not zero. The new players going through the story are successfully finding other players to do these story dungeons with.
The bribe is working, and you get a larger pool of players to ensure the party is filled relatively quickly as a MSQ roulette open to all players instead of only Mentors.