Actually david moyes was considered very successful at everton,hence his appointment at man Utd. Following ferguson was a big ask and he inherited a squad that was fading fast. He was appointed too late to have a meaningful input to the transfer activity . He didn't set the world on fire but I think he record at the time he was sacked was actually no worse than the much trumpeted Van Gall who suceeded him. I think Sunderland has been a poison chalice for pretty much everybody that's had a go in recent years.