I think we very often appointed good managers but appointed them at the wrong time.
RM and MS may have been successful if they had more experience of working at big clubs where the level of expectation was slightly lower than at Everton.
I would guess RM would be a better manager now than when we sacked him.
If you have an ambitious club, an ambitious owner, a big transfer budget... then in my opinion you need a big manager.
The game has changed so much that I think a young Howard Kendall would not be given the time and space to do what he did.