No GM is perfect, and last time I checked...games are won on the field by the players and coaches.
Yes, the GM has a big hand in getting those players...but look across the fruited plain and tell me which NFL team has a GM who makes no bad decisions on acquiring/releasing players?
For each bad decision, you can find good ones (DD, Mathis, for example).
Dunta Robinson said what a lot of us here have said, "This personnel is built for a 4-3..."
That's a coaching style and coaching decision, not a GM style and GM decision. But we had a coach who wanted a 3-4. Anybody can see that we have the beef (Walker, Robaire, TJ, Payne) for four down lineman and we have the speed with Babin and Peek, and we have the middle LB smarts in Orr to have a pretty good 4-3....but, alas we had a coach who played a 3-4.
And that's just the defense that is mis-matched. Look at our offense, too. It's just as mismatched with style and personnel as the defense is/was. The three yards and a cloud of dust offensive style is completely opposite of the players we have drafted. We've got young, dynamic players in Carr, DD, AJ, Mathis, etc., and they're stuck in 1940's helmets running up the gut and throwing hitch passes, trying to win close games and getting smacked or losing those games when they ARE close.
So if you ask me, Capers and his 3-4 defense along with his three yards and a cloud of dust offensive style have actually wasted what great talent Casserly did afford to get us. Four years of wasted NFL talent. Gone.
All because of a HC who had the right personnel, but who was too blind to see that his own style needed to change and adapt.
Nice guy. Bad HC for our team's personnel.