my current experience in D3 is already pointing to an existing droprate system.
-it improved slowly
-if i own a set item, i try it in the cash, in my own inventory, i try to gem it, to transmog it, to use the cube and myriam, to try to get more of the set from kadala…and the same week i’ve the set, then the same to get all ancient.
if i want a legendary, i always manage to get it within a week of fun mobblasting.