Please change Item/Gear drop rate in 60/70/80+ dungeons

I may not be the first person to bring this up, but does anyone know why gear in these dungeons is all random/optional (vs leveling dungeons being guaranteed, which makes sense)?

I wish they would give mandatory class drops for 50/60/70/80+ etc dungeons, because despite farming a dungeon up to 10-20 times there is some unique gear for glamour or otherwise i still have not seen or gotten because it is all class random and drops infrequently! Or another way to obtain this gear...it really sucks sometimes.