What I think he means (and what I think is a better idea) is to slightly vary at what point in the animation the water is, so not every tile is repeating the same frames at the same time. This means a whole ocean will look a lot more natural and better, because random = natural = better.
I wouldn't say no to one or two variations on the current textures of blocks though. Slightly different grain of the tree trunk, different pattern of ore in the rock. Stuff like that. I don't think it'd take up that much bandwidth or anything to implement.