the thing that makes 2H weps better
is if your casting 1-2 times slower but doing the same dps as 2x1H
thne your using 1/2 -1/3 the Hatred/mana/Rage/ per swing
till they tie in resorce cost to attack speed then 2hs win
mainly in the Demon hunters situation tho
You have it a little mixed up. And I'll fix it up.
Slow weapons = slower hard harder attacks as you said. So less fury used up for the same dps. But also you have less fury generating attacks too cause of the slow weapon speed.
Fast weapons = faster weaker shots. So more fury used to get the same dps. But also more swings is more hits with fury generating abilities too.
So to all equals out in the end. You either:
Generate fury fast and use fury fast (fast weapons)
Generate fury slow and use fury slow (slow weapons)
So it comes down to your individual game play style and what you prefer more.
This only works out if fast weapons and slow weapons have equal DPS. However, this only applies to the Barbarian (and Monk I guess, possibly Demon Hunter depending on the new mechanic).
Hypothetically, if a fast weapon and slow weapon have equal DPS, then they are equal choices for a character who generates his own resource, because your ratio of generating attacks to spending attacks remains the same, and overall DPS remains the same. If this same situation is applied to a Wizard / Witch Doctor that is primarily dependent on regeneration, the fast weapon will burn through their resource much faster, because they are not actively generating it. Yes, I know that some Wizard skills can become pseudo-generators, but that makes the assumption they are relying on those skills instead of natural regeneration.
In the case of a Wizard / Witch Doctor, the appropriate balance would be for slow weapons to have lower DPS, so that fast weapons will compensate for the additional resource usage. However, if this were the case, fast weapons will be immediately superior to slow weapons in the hand of a character generating resource.