Excessive use of mind powers over numerous centuries has to have a major stress effect. Tell me that wouldn't cause at least some premature balding.
On the torso at least, the head and neck do have hair, and the legs and feet even appear to have thin hair similar to a pig's (though it mostly only shows up magnified). Not exactly how it's described, but not outright bald.
I'm liking this revamp. While making it more streamlined kind of takes away from your typical subversive monstrous brilliance, I'm in a way kind of enjoying the fact that it makes this version seem more mystical and legendary. It's still far from the bubbly pixie mew was made as, and I think the less dopey proportions kind of make this mew seem more wise beyond comprehension, perhaps its fogged up white eye showing it in the middle of a trance. The sage white hair on the top adds to this really nicely. And the improvement of the effects on the explosion beneath its feet is just wonderful. It actually kind of reminds me of mewtwo's shadow balls in the movie, which links it to its double in a way I enjoy.