Yeah, I'm sure as the years go on we'll see other guys try to do both, and some will likely be successful. But I'd be shocked if anyone comes anywhere close to being as good at both as he is.
I still wish he could play like 2-3 years in the outfield just so he could try to add a gold glove. There's no way with his speed he wouldn't at least be an above average OFer. And we know he can throw the ball so that's not an issue.