TJ Watt was NFL ready out of College so no, he didn't.
I neither like nor dislike Tomlin. Facts are facts. The fact still remains that Mike Tomlin inherited a team that was built by Bill Cowher, injected and beefed up by Dr. Richard Rydze, that had already won a Super Bowl right before he showed up that he in turn was carried as the coach to a few more Super Bowls with. On that regard, he is the Black Barry Switzer.
Post Cowher players era, he has shown he is Marvin Lewis with a better GM. If you draft NFL ready starters for him, like TJ Watt, he can string together 8 and 9 win seasons consistently, but unless you stack the team with juiced up Pro Bowlers at almost every position and a HOF Quarterback? He isn't moving beyond those 8 or 9 wins. That's his natural ceiling.