I don't think he is a great manager, but I'll throw a few things:
1. Was given 1.7m to spend in the Summer
2. Has had our 20+ goal scorer out for most of the season, plus our best CB and best CM for large chunks
3. Inherited one of the worst squads in the league
4. He doesn't miss kick the ball, Coleman does.
Now, what I don't like from him:
1. Not backing youth
2. Inflexible system - it is not working, where is plan B or C
3. Uninspiring on the touchline - so passive
Overall, do we sack another manager and the replacement has to contend with the first four points above? What changes. The joint needs some form of stability.
It's all a mess, and Rafael has to be blamed for a big part of it, but his cards have been dealt incredibly poorly.