It's definitely yet another growing problem with the community in this game.

To answer the question of "Why we have a low level roulette", it's absolutely to get more people into lower level dungeons.

This is especially true about those first three. Players level through the 15-20 range extremely quickly. After the first couple months, the population of level 15+ players queing for those dungeons dropped extremely. The que time became longer and longer because there were so few people wanting/needing to clear one of those dungeons. Anyone 20+ in the que had far more rewarding dungeons to que for, and level 50s had zero reason to do any dungeon below 50.

The roulette changed that. For a level 20-49 player, the low level roulette gives you a change of scenery once a day and a big bonus of exp at the end. For a level 50, you get something like 80 Myth tomes. The purpose of all this bait is to improve que times for those who need to run a specific dungeon.

And it worked. However today we are in an ugly place. On one hand we have a flood of new PS4 players and most are T-E-R-R-I-B-L-E and don't listen. On the other hand, there are a whole lot of selfish level 50 jerks in the que who just want their reward and don't give a damn about helping low levels learn a dungeon and earn some exp. People like me are caught in the middle of that crap-sandwich.