I agree with you on everything aside from Mike Gandy. Gandy is a serviceable if not solid starter who has done very well at LT in Arizona. Also, at the time bringing in Dockery and Walker seemed like great moves. We were all applauding that he was finally addressing the Oline. Unfortunately things did not work out, but at the time they were highly sought after FA's.
I was a big proponent of Marv. But in hindsight, I have to say that I was wrong and that he was simply not a good GM. I do however, think that his performance would not seem nearly as dismal if he had brought in a coach with a half way decent coaching staff. But again, this was his decision and he whiffed big time.
Hopefully Nix does a better job at the helm (Personally I think he is a top 5 talent evaluator in the league.)