First of all, its is pretty striking that Michigan has had so few coaches reach year three. That says something about stability right there.
However, what those ten coaches did in year three is pretty fantastic. There were the failures: Rich Rodriguez comes to mind, as does the 6-3 third season of Bump Elliot. Past that, there are quite a few really stinking good third years. Ramzy rounds up the pre-war years and the ridiculous accomplishments of Yost and Crisler, but that doesn't much compare to this: Between 1948 and 2008 -- that's 60 years, kids -- Michigan had just five coaches. Four of those coaches went to Rose Bowls in their third year, three of those coaches didn't lose a game, and Lloyd Carr won a share of the 1997 title.
Now, none of this means anything for next year. History doesn't win football games; a competent offense with a reliable running game opposite a strong defense does (one outta two ain't bad, right?). However, it is interesting to look at Hoke's third year in comparison to those that came before. I doubt anyone is going to outright expect Hoke to live up to Bo/Mo/Lloyd, but it will be there somewhere in the back of our minds.
Michigan's schedule next year should help things quite a bit. Notre Dame, Nebraska, and Ohio State all must travel to Ann Arbor, and Michigan's toughest road opponents are Michigan State and Penn State. The only non-conference road game is against UConn. Michigan also gets a bye week after the non-conference season, and again later before the Michigan State road trip.
Matching the level of Michigan coaches past in year three may be a tall task, but one thing most of those coaches had in common is the same thing that many coaches in the same situation also have on their side: year three is when the program makes a big change from the previous coach to the new coach (think about it this way, the majority of a team's players in year two are juniors, seniors, and fifth year players brought in by the previous staff, compared to the three full classes of recruits a new coach has to work with in year three).
It is certainly worth your time to go read Ramzy's article.