Arnold is going to be judged by the CA electorate (including many, perhaps most, CA Repubs) on one thing only -- bringing business (and therefore economic strength) back to California. Buffett does know enough about Balance Sheets to know how to get this done... not that he will necessarily, but he knows how.
And considering how eye-to-eye they see social issues... think about it. If Arnold/Buffett proposed a "Social Tax Cut" for "good" corporations -- say, indexed to the Fortune 500 "diversity index" (i.e., homosexual rights and affirmative action) -- he'd have the Tax-Cut Businessmen, the homosexuals, and the race hustlers all lined up on his side.
It's probably not impossible to be both a "Fiscal Conservative" (of sorts) and a "Social Liberal" at the same time. It's simply a matter of doling out the Tax Cuts to the favored (pro-"diversity") groups, and not to the disfavored (Christian bookstores). "Division of spoils", classical Roman style.