Well, there's no Biblical number of hours for a seminary MDiv. I've taught in places in the majority world where people have very little education and are doing their best to pastor God's people. And of course historically, Baptists have in general placed less emphasis on education than Presbyterians, which was one of the reasons the Baptists were more successful in church planting in the frontier days than Presbyterians.
Having said that, there are no "fluff" courses in the WTS curriculum. We are committed to producing men who have a solid training in both Greek and Hebrew, are well grounded in the Scriptures and Reformed theology, and are equipped to teach, preach and counsel. Increasingly, students come in with lower levels of grounding in the Bible and theology, and so there is more ground to make up. Don't expect to see WTS shortening our MDiv program any time soon.
There is certainly a case for continuing study; personally I think it should be an ongoing requirement, but that's easier to do if you have a solid foundation from which to start and (let's be honest) many pastors are already overwhelmed with the challenges of pastoral ministry in an increasingly post-Christian context. And frankly, it's precisely the "hungry" students who are more likely to sign up for a 111 hour MDiv than for an 84 hour MDiv.