Sandberg? Sutcliffe? Grace? Maddux?

As the Cubs search for a new manager (again), and fans begin to project who would make good coaches in the new regime, something continues to baffle me:  Why do fans continue to throw out the names of former Cubs' favorites as prospective coaches?

I mean, come on, who doesn't love Ryno? The Red Barron? Gracie?  Sarge?  Right?  They are Cub icons, and all-of-them, fan favorites.  However, it seems borderline ridiculous, or at least yet-to-be-justified to be throwing these guys names out there as coaches for the new regime.  What is it that will make Ryne Sandberg a great coach?  What is it that will make Greg Maddux a great coach?

I can't say what it is that makes a good coach, but I think that we all agree that from the manager on down, what the Cubs need are excellent, hungry, devoted teachers of the game.  We've all complained, and all agree, no-matter-our-differences, that the Cubs' coaches as of late have plain-sucked.  It showed on the field everday.  The best teachers of the game -- or the best teachers in general, in life -- are not necessarily the Hall of Famers or best players.  That is one thing I have always observed about baseball--or any sport for that matter--it's usually the mediocre former players or no-namers that make the best managers and coaches.  Excelling as a coach utilizes a different set of skills than succeeding as a player.

So, do people really want these former stars to be coaching our players?  I just want to know what other people seem to suggest:  What is it that will make Ryne Sanberg a great coach?  Maddux? Grace?  Me, personally, I always feel more comfortable with the manager making the choice.  I mean, it's not a popularity contest.  

What does it take to be a great coach?  Who are the best candidates?  Why would former star players make good coaches?