That's fucking awesome, hope some game developers take notice, always hated ocean shores with no waves. I tip my hat to you Blizzard.
It's essentially nothing more than a particle effect, but it does look good. Perhaps in the future we'll see the 'real' deal, though.
If they can add waves like this and get them working properly with their shader tech, then it's not out of the realms of possibility that we might see more dynamic seas elsewhere in the world. Of course, it'd be even better if they could make the waves split when they hit rocks, or make players and objects "float" on top of them, but that's probably asking a little too much. Again, it could just be an animation on that area of the water.