I agree that is a problem, but I don't think that the new gear thing would make this worse. It might not make it better, granted, but we already have people queuing for one role and then actually playing as another so they get the "right" loot, and I think that's probably more detrimental to success than people who queue for a role and then just do that role poorly because they don't know what they're doing.
And DPS queuing for healing or tank roles for the speedier queues, regardless of the way loot is handled, has been a long existing problem. But at least we won't have the ridiculous circumstance of running with two healers because three of them swapped to DPS specs for that caster DPS trinket that drops from this boss, and running with a bunch of people DPSing [poorly] in tank spec because they really desperately need tank gear but can't actually queue as tank because... they don't have the gear yet. The whole system now just encourages people to do a lot of silly things in order to get the gear they want, and anything that corrects that issue is probably going to be a move in the right direction.