To be honest until we actually get into the content and see a lot of the fights it is going to be harder to tell. For the most part going into new content you should shoot for EHP because even if fights rely more on avoidance there is going to be some sort of EHP minimum and chances are we won't be at it when we first start in IC. Therefore I'd say blood draining, but that may change if there are a lot of fights where you need to stack avoidance or something. I still think that we'll be gearing/gemming for EHP, but we'll just have to be more mindful of avoidance and its importance, rather than being able to blatantly ignore it right now. I don't think GC is saying that we're going to be gemming/enchanting for straight avoidance, but that the raw avoidance on gear might not be enough for tanks to skate by on any more and still ignore upgrades that might be a 100HP loss but 1% increased dodge.
But like's been said, it's really going to come down to game mechanics, long fights where healers could have mana problems but don't really have to move while the tanks take damage, then we're probably going to want an EHP minimum then go for dodge and such (think brutallus), but if there are going to be fights where healers have to move a lot and tanks just have to be able to take damage (think Algalon) then we may be going more towards stam.
As the Zen Master said, "We'll see."
Edits: I should stop typing with gloves on or something.