I think the main ability demon hunters have from a design perspective is adaptability. That is being overlooked here.
When low on gar, you have the best dps producting passives in the game. You need some level of reflex and skill to use them effectively, but they're there. As your gear increases you can swap them out for more utility and customization, which most Demon Hunters do. Vengeance and Tactical for speed farming, Perfectionist if you need the survivability, or one of the many other completely viable skills we have.
You want to be the omgdps 1 shot everything class while retaining utility, and while i salute your embracing your complete madness, this is just not going to happen in reality. While I don't agree with nerfing anything in a dungeon crawler, blizzard has WoW on the brain and feels like they have to balance and rebalance constantly (this also provides a boon to the RMAH). So if you're new to this mentality, welcome to the roller coaster. You can either ride it out, or level 1 of everything and be a fotm player.
The Demon Hunter class has one thing I really don't feel any of the other classes have, and that's a personalized feel. You can be very effective using dark horse builds, and the dropoff isn't exponential from the cookie cutter. Barbs, Wizards, Monks, and WD's all have this problem, there's the one build, then there's everything else. For Demon Hunters, there's tons of variation now, and while it took me some time to come to terms with the orginal round of nerfs to DH's (SS/NT/IAS nerfs), I feel like they're one of the most complete classes at this point in the game. Even the "fun" builds can anhilate a3 at mp 3-5.
To put it simply 1.05 just hurts the DH. The reason is because in any build you want something that fulfills 2+ of the categories of damage / defense or life / mobility / resource generation. What Blizz did was to take the one skill (ToC) that fulfilled 2 of those categories well and made it yet another skill that's a single category skill with some side benefits. Most classes have at least one skill that fulfills 3 of these categories while DH's are lucky to have one that fulfills 2 well. So now in 1.05 you'll have a bunch of new builds because NO DH skill fulfills 2 of these categories well (even with passives directed toward it) much less 3. So you're filled with a bunch of single category interchangable skills with VERY little synergy between one another. IMO it's terrible and just shows how little the designers play the DH class.
Additionally, we have the monster power introduced. Essentially 50% increase of hp per level. Who does it hurt? The classes which rely on damage to create quick kills and unable to do sustained tanking w/o taking massively away from their DPS. Aka the DH. Thus we went from the 2nd fastest farming class (thanks to ToC) to probably the 2nd or worst farming class becuase of how poorly damage scales and how poor our resource generation and how much our subsequent AoE skills need these resources.
So in the end I went from a 130k DPS 2 elites per minute farmer in 1.04 to something that will never farm above MP3-4 because of the HP to damage relation. I could get the best gear in the game and up my DPS to 380k but guess what, that's still only somewhere between MP4-MP5. Otherwise I'm relegated to kiting (going over your own footsteps 3-5x) where any class that can get into the middle and take damage while putting down damage (Wiz, barbs, some degree witch doc and monks) will do better as they can hit a lot more targets without having to run away. In the end, for end game DH's are now probably the worst class, especially when compared to how much you have to spend to get there.
Sadly, I saved most of 1.04 and got crap drops even with 350+% MF and through 70 levels of crapagon with the last 40 at 403% in 1.04. Now in 1.05 I'm probably going to shelf my DH for a bit for the barb as really seems that's the only way to go if you care about farming.