Just because he is a wealthy movie icon turned politician makes him no more American than the infant born 15 mins ago.
Not that long ago, a young man immigrated to the United States from Africa, work menial labour jobs to save money and later acquired his green card - with one goal in mind, to join the US military. He was killed during Operation Enduring Freedom - since we're into comparing how much of an American people are, I would say he wins against the good Governor hands down.
A lot of people are star struck by him, and not much more. I would much rather seen a "average" American (ie. those that may have the smarts, but not the big money to run on) have the opportunity to run for President before allowing a Constitutional Amendment for one man whose biggest contribution (as of now) to this country is making entertainment.
While I believe him to be of good character, and often very charitable with his time and money - he has hardly proven himself to be worthy of such a change to such an important document.
My .02