Actually, I know Coryell had Fouts as his QB, but that was before my time, so I never got to see it in action.
Neither have I, but at least I know about Coryell and his great offense lead by Fouts and Winslow.
Walsh's system which worked well with his personnel won Super Bowls. Of course he also needed a defense to pull it off as well.
What makes you think that coaches known for offense disregard defense? In Walsh's first few drafts he concentrated on Defense, especially the famed 1979 one in where he basically picked up half of his dynasty D (including one Ronnie Lott).
So by your logic, Warner soon will be seen as a bad QB as well.
Obviously you've never taken a logic class

Warner had some sustained success, enough so that his starter was traded away. That never happened with Mitchell or Johnson. However, the tide is turning, actually. Warner is being seen by many, now, to be a product of the system and not that good. People forget the stats he put up.
Bulger looks good now. We'll see how he does in the long run.
Oh and while we're trying to praise coaches here, there is also something called having good quality players on your team that help immensely.
The BEST coaches get the most out of their players, however (like Parcells).
The West Coast offense isn't working because they don't have talent at the skill positions.
You do realize that it takes time to get the right personell to run complicated offenses, right? Just because Morningweg was there for the years before, doesn't mean Mooch would put the same people there.
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