The hunter preview is covered all over the place. From a DPS standpoint we know they are focused (pardon the pun) on damage. That's the key term for all the mastery benefits. The bummer is that the new abilities are mostly focused on PvP. They threw in tasty gravy, but I don't see any meat.
I suspect focus will actually be a lose for us. Here's why: Today when you want to go all-out burn-them-now, you pretty much know if you can and if you have the mana to do it. You've got a cooldown or two you can pop. But you will be using all sorts of your resource (currently mana) in short period of time. With focus, you will be constrained on how much you can do. There isn't a built-up reserve like with combo points. There isn't a mana pool you've been conserving. There are 100 focus and you can burn through it with just a shot and a disengage. I suspect that when we want to unload on a target we'll be watching our focus and waiting instead of watching the cooldowns of big abilities.