So, I've got some concerns here, mostly based around the Demon Hunter and the way its skills are built in conjunction with its resource system. No one seems to visit the Class-specific forums, so I thought I'd try here.
If you take a look at the Monk and the Barbarian, they both use a 'rage' mechanic for their respective resources. You use skills to build up the resource, and then use different skills to empty it.
This works. If you use a big, heavy, slow two-hander, you'll build rage or spirit slower, but your resource spenders will do more damage. If you use a couple of fast, lower-damage weapons, you'll build rage or spirit at a much faster rate and use less-powerful spenders more often. This is cool, it all evens out in the end, more or less.
Hatred and Discipline do not work this way. The DH has to wait until its resources replenish to use its skills again.
Considering this, why would anyone prefer to use faster, lower damage weapons? You have to spend twice the amount of resources to put out the same damage, with no way to mitigate that outside of using specific passives or runes that, while possibly solving this problem, diminish your potential damage and/or utility by denying you the use of other runes.
I realize that Blizzard is doing some work with the Demon Hunter, but it doesn't sound like they're really planning on overhauling the system or anything. The only way these kinds of problems worked themselves out in DII was because every class used Mana and Mana leech was rampant almost exclusively to solve this kind of problem.