I don't really think you can compare golf to tennis. Golf is such an individual sport (with the exception of Ryder, Walker, and President's Cup play, of course), that you really don't compete against another player, as you do in tennis. You're really competing against the course, and against yourself.
I think Wie's talent and potential are limitless. I think she made the wise decision to turn pro. I mean, guaranteed $10M for just turning pro? Anyone would be a fool to turn down life-changing money like that.
As for her career, I expect it to have a similar trajectory to that of Mr. Eldrick "Tiger" Woods. Remember, Woods tore up courses his first year or so, then cooled off. Everyone was talking about how maybe he was overhyped, etc., etc., and now, at age 29, he's the undisputed best golfer in the world.
I expect Wie will have a ton of success on the Asian tour, but she'll falter a bit on the LPGA tours (she gets six sponsor's exemptions, I think. You have to be 18 to turn pro on the LPGA tour). Eventually she'll play within herself and dominate the LPGA the way Tiger dominates the PGA.
Then it'll be on to challenge the men!
In short: Michelle Wie is the real deal. Watch her rising star!