I agree with the latter statement, but the former is predicated on a bit of a misunderstanding.
There is no Mike Martz system, per se. The secret is that there is no secret. Mike is against the notion of an "offensive system", in the sense that a fellow like Bill Walsh would define the term. Martz custom tailors the offense to fit the personnel that he has. The game plan is always the same: Use motion and formation to put my biggest play makers against your biggest weaknesses. The game plan is just a collection of plays Mike thinks will work in this regard. Now, he does want to pass first, and pass aggressively to get the lead, but this is a very general idea.
Now, you may want to call that a system, but I wouldn't. It is more a philosophy about using whatever playmakers you have on hand. A documentary was recently published by a bunch of Astronomers titled "Journey to the Edge of the Universe". The funny thing is that they would be the first to tell you that there is no such thing as "the edge of the Universe". Ergo, the title is just a catchy title. That is all. Calling Mike Martz's approach a system is similar to talk about "the edge of the universe". It is a catchy title, but there is no such thing.
The reason why Mike is so consistently successful in raising the fortunes of offenses and teams is pretty straightforward: He is not one of these fucked up egomaniacs who want to replace all the players he's got so he can obtain guys who will run his highly dogmatic system. Such coaches always guarantee you several years of turmoil and rebuilding (which might be necessary anyhow). West Coast coaches are these kinds of coaches, in general. Lombardites are absolutely those kinds of coaches. They'll cut all kinds of good playmakers to clean house and implement their power-running attack. I hate those little fuckers with all my heart and soul.
Mike doesn't need to cut everybody and start over. He will look hard and long at the abilities of his men. He will figure out what they do best. He will figure out how to employ those abilities to the fullest. He will create formations, plays and motion that will let you shine. You can understand why Mike is a very popular guy with his men, and you can understand why head coaches feel threatened by him.
I am going to tell you flat out: Dogmatic systematic coaches are the worst thing possible for your organization. Flexible and adaptive coaches who use the talent you have on hand are the best thing possible for your organization. Scott Linehan was a dogmatic systematic coach, and he will forever be known as the guy who killed the Greatest Show on Turf, the Show Mike Martz created.