I think u miss out another man who has been part of this generation of rubbish who has succeeded at international cricket- don't worry people miss him out all the time, Shivnarine Chanderpaul. Although we are in quite a dire situation, Gayle and Sarwan for all their underperformances and inability to perform under pressure do average high 30's in test cricket. That is the best we have at the moment except for Shiv who averages mid-40's. I believe Gus Logie has already had his time as West Indies coach and didn't really do anything as coach; maybe though he was hampered by the fact he had Lara undermining him all the time and the poor infrastructure.
I don't believe in having a a coach, maybe a manager to oversee things but what i would have is specialist coaches. Bowling I would have Courtney Walsh, Holding is too engrossed in his media career at the moment. Batting could be whoever, fielding-somebody like Jonty Rhodes or Trevor Penney, and we need a fitness coach.
However as Remie said, all of this; selectors, coaches, support staff, players will not make any sort of difference until the WICB is either dissolved or reformed.