First off, I'd like to say hello to everyone!

next, being a fan, yet not a historian of the sport, can anyone give me some examples of good and/or successful trainers, directors ,or coaches of the game (whom have never been successful players themselves, or not have ever even played). Also , what do you think are the pros and cons of trainers, diretors, coaches whom have played vs. those whom have not. PLEEEAASE give me some examples of these individuales at any level, league or plataform of the sport, as this is a topic of GREAT DEBATE among many players/fans in my circle.