I think he'll win at least 3. He has fixed everything that was wrong with his game. Lendl has fixed his forehand and serve. He has good topspin on his forehand now and he has a great first serve %.
The thing is, it all depends on whether a generation of players comes along to challenge him and Djoker. Much like Federer had easy pickings until Murray and Djoker came along and immediately started beating him, Murray in 2006 and Djoker in Montreal 2007. If a few talented 18 year olds emerge next year things could change very quickly.
If they don't though, Murray could reap the rewards of a weak field, like Agassi was able to in his 30's for a year or 2.