Some players do an amazing job as managers in the future, others, horrible.
Maradona, it will be hard to say. I think he can maybe bring something new to the table. The man has lived an amazing career, and was something out of this world, and imo, changed the face of football like many in the past have (Pele, Cruyff, etc).
Like Bobby said though, he seems to be getting his life in order, and finding his role as what he should do now that he's not the player anymore.
One thing though, imagine the how the players will feel. THE Diego Maradona is managing them, they will want to impress him, and will do anything to get that 'nod of appreciation' from him. I know I would be giving 200% if my football hero was training me.
I say give the man a chance.