So 7.1.5 dropped, and people should have had time to get used to a few of the changes. I've seen a lot of bitching on the forums, which is surprising to me, because I think 7.1.5 was one of the best patches they've ever done in terms of keeping everybody happy.
They managed to address and adjust quite a few things without majorly fucking up everything else, which is pretty legit.
Complaints they addressed:
Mediocre single target damage: The buffs to several abilities (annihilation and chaos strike), and to blade dance increased our single target dps pretty substantially; most people seem to be reporting 30-40k dps increases (or more in some cases) which is very noticeable. This puts us in line with the other good classes and specs, rather than feeling like a red headed step child. If were being honest. I'd way rather feel like the red headed step child for emereld nightmare and feel awesome for the actual raid they spent a bunch of time on - make no mistake, EN was the highmaul of this expansion, and the fights were blah, boring, easy, and it was a pretty meh raid overall.
Cookie cutter builds: there are currently two completely viable raiding builds right now. I don't have the ring or belt or shoulders, the three largest single target dps legendaries available for demon hunters right now, and I just did 513k dps on heroic guarm in a 3:40 fight while testing demonic. There are THREE completely viable mythic + builds right now, and room to swap them for eachother based on what legendaries you have.
Legendary disparity - AotHG is an awesome legendary, but the disparity between the haves and have not's was way too large - getting to have full fury and never running out at all times when others had to deal with that was way too strong - you literally could not be competitive without the ring. It's still an awesome legendary and it still puts you significantly ahead of others, but its no longer a flat 10% + to your damage. The most frustrating thing about legendaries was huge dps differences based on completely uncontrollable RNG, and bringing them closer to eachother is only a good thing.
Fury generation - lots of people who haven't done the math are pretty upset right now, but right now if you're playing havoc correctly, you should have less downtime than you did in 7.1. Dead spots of "welp, guess DB hasn't procced for 8s during meta, guess I might as well run off into a corner and die because my damage is gonna be useless now" are fewer and further between, and that's not even accounting for the two set, which is a large fury generator.
Basically, we have more available talent choices, we have more completely different ways to play the spec, were doing extremely good damage (even with the 2% flat nerf to all our abilities, which honestly, I'm surprised that's all that they hit us with). It's no longer quite as crucial to have the "correct" legendaries, because you can adjust the build your running based on whats available to you.
All in all, I think 7.1.5 was a really really nice patch, and I'm very surprised the DH forum is so doom and gloom about it. The only really true complaint that I've seen from people so far is that all the talent trees are really easy, but the fact of the matter is, demon hunters have never been difficult and if you wanted a complex agi melee spec you should have been playing a hit combo monk or a feral druid from the getgo.
Edit: Not to mention from a pvp standpoint, even with the changes were still really strong, and demonic is hilariously good for mythic + right now. Was running 13-15's yesterday in demonic, and the modifers are bolstering/skittish/fort, which meant there were several AoE pulls where I'd snag aggro on 5-6 mobs and it just didn't matter even a little bit...Think about that for a second - it doesn't matter that were pulling aggro on 15 bolstering/skittish/fortified because were outhealing the damage. Not to mention, regularly finishing bosses in the 900-1.2m dps range doesn't suck either.