That's actually a very nice video. One thing I felt I disliked in GW2 was the amount of button bashing and spamming skills as they come off cooldown, this video shows you that this is not the way the game should be played in order to succeed. It sort of makes sense as I felt I take a lot of damage in game.
I already knew I was playing wrong and just figured over time I will pickup how to play properly, this video though explains it first hand straight from the developers mouth. Ideally they could do with some combat tutorial as really, at least during these betas, you just get given a weapon and pushed straight into combat with one skill. You have no idea what to do other than spam it.
I really wanna get started with the game already. I figure we still have 3 months at least of betas