Not sure how item balance was previously, but I can tell you as far as Harbinger goes it's out of whack. I'm level 89 now. I have seen ONE exalted shard drop, which is the exact same number of exalted orbs dropped. The funny thing is the exalted shard dropped super early for me, in one of the first 4 acts, before the new acts. I have run so many maps at this point and have not since another exalted shard since. Mathematically you would think the shard should drop 20x more frequently that the orb itself, but that doesn't seem to be the case, or even close.
In this whole time, I have also never had a divine vessel drop. Not sure if bad luck or if it really is just that stingy.
For now, whenever I see those harbinger guys I just try to avoid them, they take too long to kill for what the rewards are, so it's just not worth if for the few alchemy and alteration shards that usually drop. Sounds like the changes will address some of these issues, but will have to wait and see the implementation.