Randolph could be a franchise player. He is one of the most gifted low post scorers in league history. The problem is, like Derrick Coleman, his head isn't on straight. Mike Dunleavy unfortunately isn't the coach to do that. Paul Silas barely managed Coleman enough for half a season. You need to find a coach willing to say to Randolph "you should be owning every one else in the league in the low post, while using your size to at least be average on defense...until you do that, you'll be sitting."
Not that this would faze Randolph who already has his big contract. Maybe as he gets older, like Coleman, he might recognize how much he's wasted his talents and put in a couple seasons of actual effort. Coleman basically bailed out the Hornets and Sixers once each by trying for half a season despite being well past his prime.