I don't know why people thin he would automatically be a good coach.
He might be good, but...what is going to say about cheating, taking pills from a coach when you don't know what it is, using shoes in an Oly trials and games to win medals which were not legal (you can't wear shoes that aren't available to the other runners - see 2016 trials and 16 games shoes), claiming he had answered every question about doping when he has actually answered almost no questions about doping and running for a coach who got banned from the sport.
He may know how to make out a workout and about recovery, but don't expect him to be great on teaching morals (right from wrong), learning to speak up when you see something wrong, taking stand on issues that impact the sport, etc.
If you are looking for a leader, you'll probably be disappointed
If you are looking for a technician, you'll probably be pleased (as he worked with the best technical coach in the business in Alberto Salazar.
My conclusion is he would make a great assistant under someone else's leadership, but not necessarily be a great head coach.
