I remember reading that they wanted Arnold to stay away from a few Republican gatherings because he attracts too much attention and takes away from whatever they were gathered to do, which isn't bad. I think you'll get all the regular Republican voters, but then you'll get the people who don't know much about politics as well as the fans who will vote for him.
I also think he has a lot of dirt in his past to hide though. He's come out and told about his steroids, so they can't use that card on him but I've read other articles. There was a time during the filming of Termanator 1 where he reached up a female producer's blouse or something and grabbed her boob. When she tried taking it to the press and complaining, Arnold's "people" shut her down and so the issue stayed quiet.
During campaigns they dig up anything and everything on you. During the 1993 Clinton campaign, the Republicans were offering one million dollars to the person who could find a picture of Bill Clinton burning an American flag in an anti-Vietnam war protest. They have searched far and wide and have confirmed that such a picture does not exist.
Another problem is having a Republican move into a Democratic stronghold. They don't call it the "left-coast" for nothing. But with the recall campaign against the current governor, even if it doesn't succeed, I think there might be damage done to the Democrat's reputation in the state.
Then there's the issue of Condaleeza Rice, doesn't she want to run for governor? If she does, it will be a good argument to say that she's the "serious" and experienced and educated one while Arnold is all charisma, which isn't neccessarily the case, it's just what could be argued.
I'd like to see Arnie become governor of California. It would certainly spice things up a bit just like Jesse Ventura did for Minnesota. But I don't think it will be an easy road.
Just my two Canadian cents