My concern with him is that he's yet another celebrity (like Schwarzenegger) who talks tough but once he gets there, you find out it's all show. (Remember Arnold's talk about disbanding the unions in Sacramento? And how'd that work out?)
I think you answered your own question. Yes married life. Yes business relationships, that include gambling and real estate development, which are EASILY the two most corrupt industries in the country. Even the low-hanging fruit would be enough for a competent opposition campaign manager to sink his chances.
Whether or not Trump would be an effective politician, is another story. My guess is, he would not, especially when his first brush with managing government bureaucracy is with the biggest bureaucracy. That's not a recipe for success.
Since you asked about Arnold, apparently he didn't realize that California elects a Governor, and doesn't coranate a king. He may have had all the best intentions, but in California, all the real power lays with the legislature, and with the "people" via the ballot initiate process. That's why California is un-fixable.