Since 2.1 we've had the same 2-3 dungeons in a roulette for 3-4 months at a time. It burnt all the dungeons out. It's not even fun going back and experiencing it due to nerfs or the fact you could run expert every day and roll the same dungeon every day for 3 weeks (Looking at you Nevereap).

Also I'm pretty sure most players doing combat content would have done the 50 dungeons, as a lot are required for the MSQ and in general for the roulette.