I have 2 groups of 4 70s on PVE that I played under patch 2.2. For my PVP toons, 1 group of 5 70s I played under patches 2.2-2.3, another that I played across the upgrades from 2.3-2.4.1 and another group of 60s on PVP under patch 2.4.1-2.4.2 so far and I really haven't been able to tell any difference in the same quests, except for a few notable exceptions where drops were changed from random % to 100% always and a few others that were changed so the whole group got the drops. Speed of leveling didn't seem to change much either, aside from me getting much more efficient at not doing zones or collection quests to speed things up dramatically since 2.3. For those quests that were always a low drop rate, I can't see any difference. The ones that were a huge PITA are still a huge PITA.