I think everyone will agree with me here that LFR full sets are quite hard - actually way too hard to complete / gather.
During Legion Trial of Valor - there was a quest to obtain a full set for XYZ difficulty by killing bosses.
I propose a similar setup :
After 4 full clear on that specific class - you unlock the full tier for that class.
That would increase the amount of people queueing LFR and also making completing the LFR set doable in a reasonable time.
If you agree or have a better option - please list it here.