Anyone who suggests he's solely at fault for the relegation is being myopic - I think recruitment in the premier league clearly wasn't good enough so he was left with a squad not up to the level but his refusal to adapt his style of play in line with the reality that we were clearly underdogs in the division was a major factor in relegation.
All in all I think he's a nice bloke (unpopular opinion round these parts i know) and a decent enough manager who's dogmatism played a major part in his, and our, downfall and will restrict him from managing at the highest level.