IMO another factor for SVG leaving is all the egos.
2 years ago he had Wade,E Jones,C.Butler,Odom,Grant and a bench of Alston,Haslem,R. Butler, and Allen
no one expected them to do well, and there was no pressure.
Last year he had Wade, E Jones, D Jones, Haslem, Shaq with a bench of Dooling, L8, Anderson, Zo(half a year), Doleac, and R Butler.
More pressure because of Shaq and Wade's rookie year, but at the same time his job was easy. Get Shaq the ball, and everybody else will feed off of him. Everybody else on the team let Shaq do his thing, and they played better because of it. Wade also got better as the season moved along. Again he only had to do two things, Get Shaq the ball or let Wade iso his man.
This year (even without Shaq) he had to coach Wade,JWill,Walker,Posey,Haslem, Payton, Kapono, Simien,Doleac,Anderson, and Zo. With Shaq back it would be easier for them, but w/o Shaq SVG would have to find a way to get all these players involved. Missing Doleac and Anderson for the last couple weeks has hurt as well.
IMO the Heat not only needed a player that demands a lot of respect like Shaq back in the line-up, but a coach that has post season credentials, and is not afraid of making changes to line-ups. Riley is better suited to run this team.
IMO
SVG-Teacher, good for young teams searching for an indentity (Heat 2 years ago, Hawks, Raptors, etc.)
Riley-Better suited for veteran teams where all he has to do is call plays