Kingston will be a very good hire. Go read what national college baseball writers say about him. This is a good "get." He's turned two bad programs into winners at places where there aren't many resources, no fan base etc. A guy like that can certainly do great things at a place like USC.
College baseball coaches don't jump like football coaches for lateral moves. There's no reason for O'Sullivan to come here. He has money, no state income tax, getting a renovated stadium, works a prime state for recruiting etc and works at place where there is probably less pressure to win than there is here (and he's been winning just fine at FL). So why would he come here?
People that are bashing the idea of Kingston as a the HC as USC are doing so because they just don't know him... but Ray Tanner does and many folks here think Ray is 'god' when it comes to college baseball, so I'll go with his judgement on this one!