Personally, I find the OP to be extremely well thought out and reasonable. As a DH with almost 950 hours and having played since 1.02, I've many times felt that to keep up with other classes it's taken a much larger investment in gear. Now, having said that, I also feel that my DH is doing pretty darn well (although I've definitely had to pay for it, and no I don't mean RMAH, I've farmed for every piece of gear I have), and partly because of the fact that it takes so much more of an investment in gold and time (to learn the char and get good at using it) those of us who CAN play a DH at higher mp get a bit more of a right to brag ;)
For my two cents, the biggest issue I see with DH is hatred regen. I've been thinking for a long time now (probably since around halfway through 1.03) that there really should be a skill like Nightstalker for hatred (or that NS should replenish hatred as well as disc). I think that if something along those lines were to be implemented, DH would instantly become a MUCH more viable class at higher MP. Allowing us to use our high DPS skills more frequently would enable us to trade some of that base DPS for more defensive gear, effectively re-balancing the equation and giving us more flexibility. Those that still wanted to go glass cannon would be able to more effectively, and those that wanted to add more survivability for higher MP could do so and still maintain DPS output. I truly hope something like this happens, because I really don't see myself doing all the work to make another main char at this point ;P
A final thought: One area where DH does shine above the other classes is in damage output from multiple skills simultaneously! While we may not be able to pump out the huge hits from single skills like the other classes, what we CAN do is to hit for very reasonable numbers with multiple skills all at once, doing immense amounts of total DPS. For instance, in my higher MP build, I can use ST-EB for crits up to 700k (3x each of course, maxing each ST's damage at 2.1 mil), BS-TB or BS-VE for crits up to 400k, have a sentry going for anywhere from 50-200k, AND use Rain of Vengeance-BB for hits up to 700k again, all happening simultaneously. This kind of usage effectively pumps out HUGE amounts of actual damage (almost all of which is AoE) using only one big hatred spender, and is really where DH can excel. I haven't actually tested what my effective DPS is doing this, but I plan on doing so now and I'll report what I find. In any case, it certainly is another option for increasing dmg output without having to spam high hatred-spending skills.
Edit: Just tested, doing 920k effective DPS against Ghom with no follower, mp5.
I love my DH, will continue playing my DH, and do not feel the need to switch to another class, but cmon guys, EVERY class has had and continues to have balance issues. So, if you don't want everyone to start calling YOU a whiner and a QQ'er the next time YOU post about how blizz could improve your class, please take posts like this and the OP's as the constructive criticism they are, we're all just trying to make the game better! Feel free to respond and disagree in an equally constructive manner, but just butting in to point fingers and troll people doesn't really help anyone.
Edited by Soul777Toast#1894 on 2/20/2013 11:36 AM PST