Wouldn't sack him but I think he should leave at the end of his contract. Let someone come in who can properly utilise the creative talents that aren't being used by him.
I may be misrememering but I know he took a mid-table team and completely failed to replace the key players so they were a shadow of themselves by the time they went down.
Takes forever to make a change and it's the stupidest one he could make. If I'd known his first change would be Henderson I'd rather he just play the same 11 for the entire 90.