I think he's a narcissistic jerk.
The only specifics I can glean from his diatribe are:
- S&S was somewhat slow to pay his advance. (And wouldn't it be nice if he could spell the publisher's name properly?)
- S&S didn't agree to his idea of a money-back guarantee.
- S&S didn't use his cover ideas.
These are S&S's great crimes against him? Egads!
Oh, but apparently there were times when people at S&S were not immediately available to him--because of course HE is the only author anyone at the publishing house needs to deal with and should be everyone's priority. He wants what he wants when he wants it, and when he doesn't get it, he has a temper tantrum.
The rest of it--most of it--is meaningless blather. His recommendations are just generalizations that are empty of substance. He's rude and nasty and he doesn't know the first thing about writing, if that letter is any example.
S&S's biggest crime was signing this self-absorbed blowhard to a contract in the first place.