I think their key problem is the coach.. MDA. I liked him before but I was blinded by Nash's ability to run the team rather than his actual coaching.
MDA doesn't teach defense. He rarely goes over them (sounds similar?). He doesn't bring out the best out of his players. He would just keep using his "good" players until they are tired and worn out.
Gentry, on the other hand, encourages players to do their best. IE: Dragic against Spurs, running plays for Richardson against Lakers when he was hot, and letting Hedo play what he does the best last night. I don't see that from MDA..well, from my limited Suns' games I've watched. Not sure if he has changed in New York but I highly doubt it.
I don't think Amare is trash but on a poopy team like NY, they need to pay "premium" ($100 Mils) to attract any serious player. Hell, even Lebron didn't want to go. They are blaming a bit too early and they need to change coach.