We have him to be grateful to for keeping us in the division. For restoring some pride after a frankly dreadful period. For laying the foundations that underpin a lot of our success today. And for quite a few very enjoyable seasons along the way. All somehow achieved at a time when we were constantly robbing Peter to pay Paul. Quite how we progressed as we did, in the circumstances, is near miraculous and I'm not sure many other managers could have done it or would have had the stomach for it. The regrets are the lack of trophies and the way he conducted himself on leaving, but the positives by far outweigh the negatives.
I wouldn't go back for him, and said the same in the summer, much as I think he can still do a job with Sunderland. I think he'd have continued to do a good job with us if he hadn't left, but that's purely hypothetical now. Wishing him ill is simply bitterness at the fact he left (and how he left). For me, his departure and the circumstances that followed don't even come close to negating what went before.
Legend is maybe too strong, but to call it a 'lost decade'...well that's just ignorant.