Great Players and Managers
Very few great names come to my mind when I think about great players becoming great managers. Of the top of my mind, I can think of Johan Cryuff, Franz Beckenbeur, Frank Rijkaard but no more. On the other hand, great players such as Graeme Souness, Ruud Gullit, Bryan Robson have not achieved much success as managers.
So, what is that X-factor that managers are supposed to have in order to become great? Providing inspiration and confidence to the players, i suppose is the most important thing that makes a great manager. Aston Villa, until recently was down in the dumps, but after Martin O'Neill took over, they have been undefeated and are in the top five after 3 matches. It's basically the same set of players his predecessor O'Leary had but then O'Neill has been able to instill confidence into the team through his great approach and charismatic persona.
Also, managers do need some luck. Money for new players and fewer injuries, as in the case it has been with Mourinho at Chelsea, can pave the way for huge success. But will Roy Keane be able to build a team at Sunderland with limited money but great fan-base and take it into the Premiership within at least 2 seasons? If he does that, he can be considered a good coach but for him to become a great one, he will have to achieve nothing short of what he achieved as a player at Manchester United, be it with Sunderland or any other club.