There's just no way you can put Barnes in the top 15. Off the top of my head:
Coach K, Cal, Donovan, Pitino, Self, Marshall, Belein, Izzo, Roy, Bennet, Miller, Ryan, Boeheim, Brown, Few, Wright, Hoiberg.
There are a couple more that you could argue as well, and you could even argue a couple of those. I think Barnes is a borderline top 25 coach.