He is universally well-liked by fellow coaches and colleagues. Consider the fact that notoriously hard-headed veteran coaches Norv Turner and Mike Martz were happy to work UNDER Nolan as assistants. That tells you a lot about Nolan's ability to play politician with the NFL's elite.
And to his credit, Nolan came in with a clear sense of what he wanted to do.
-- How to build a 3-4 defense: inexpensive linemen, stockpile LBs, top-notch secondary (Nolan was an ex-DB, after all).
-- How to build the personality of the team: college captains, seniors, leadership experience, free-agent veterans he could trust (ex-Ravens galore).
-- How to present the image of the team: professional, suit-and-tie, old-school, tribute to father.
Gotta give him credit for coming in fast and aggressive, and it was looking good for the first couple of years. Nolan's strategy in the drafts and free agency was to play conservative, get high-character guys who play hard. But that's not enough to build an elite team. Sometimes you need to gamble on the dangerous guys with "upside." But Nolan systematically stayed away from those types. And as a result, we've got a team full of high-character guys with limited upside.
It was a conservative and safe strategy to rebuild a crappy team into a decent one, and the 2006 team was indeed decent. Unfortunately, the injury to Alex and the horrendous response to that situation (not getting a proven veteran QB? Seriously?) has led to this fiasco. Nolan made a few big mistakes, will learn from them, and my guess is that he'll get another coaching gig elsewhere (again, the guy is a master politician).
As for the 49ers, if it were up to me, this offseason I'd focus on D-line and QB.
> In rounds 1-3, draft a DE, DT, and QB.
> In free agency, sign a run-stuffing DT and a veteran QB.
The current OLs and DBs have talent, and the other positions (RBs, LBs, WRs) can be replenished easily. D-line and QB are historically positions in high-demand, so we need to devote significant resources (high draft picks, FA money) to them.