First of all, was there a pun intended with the mention of "face" in the title? God help us if someone decides to post a picture of Rhodes posing in front of that LED mirror one more time.
I don't think Cody Rhodes is going to be the marquee star of the WWE (like John Cena or Randy Orton), and to be honest, I don't see how you can really make a case that his beating Mark Henry makes any momentum for him whatsoever. Henry's designation is jobber to the stars, and Cody hasn't exactly been on a big time roll on Smackdown. I guess WWE decided not to bury Rhodes by getting squashed by Henry.
Rhodes will be a solid performer like his brother, and he might possibly evolve to the point where he might challenge for the world championship on a PPV. But I don't see him being the "face" of the company where mainstream appearances, merchandising, movie deals, and consistent main attraction status are pretty much the norm in today's wrestling market. I don't see Rhodes attaining that status. He might get to the level of a Sheamus or a Wade Barrett someday where he will be the challenger to the big name. But I don't see Rhodes being THE face of WWE now or in the future.