Very hard to judge given the circumstances.
On the positive side he is clearly building a good team spirit in farcical circumstances; the team are playing hard, Fitzpatrick is having a blast and Christian Wilkins is running around all over the place to celebrate TDs. Whatever it is he's selling the team seem to be buying it. I've been impressed by some inventive playcalling around onside kicks, fake field goals and fourth downs, although I guess it's easier to play balls out when you aren't expected to win. The discipline based on the penalties and tackling stats is a great sign, and although that's gone to **** in the last couple of games I'd imagine a significant cause is the swift turnover of new guys in the secondary.
On the downside there are the odd personnel decisions (McCain, Stills) and the public flip-flopping over Rosen and Fitz. I certainly put the latter down to inexperience and naivety, and hope that in time he learns to manipulate the media rather than vice versa. It's disappointing Rosen isn't playing, to the point where it makes the trade a waste of time, but I understand why and he has obviously prioritised the motivation of the players and carrying that into next year ahead of further evaluation of Rosen.
He's done a good job this year, but it's hard to say how that will carry thorough given the different circumstances we'll be in next year and then again the year after. This franchise is going to go through a very fast transition and he's going to have to adapt his skills to manahge that change. Maybe he's in his element getting the most out of young street FAs but can't cut the mustard with high profile draft picks and free agents. Maybe he excels when the chips are down but can't translate that to success when it's expected.