This argument gets thrown out all the time "needs to go and get experience" "needs to 'prove' himself somewhere else first"Ferguson works on passion. Passion only works for so long before you need actual tactics. That's why he REALLY needs to go somewhere to try out a team for awhile.
I would argue that he has had excellent experience. He has worked closely with 5 or 6 (very different) Everton managers now. He has seen what does and doesn't work from each managerial style.
If he has learned well, he will take on board the positives and learn from the mistakes of others.
In most industries you will find that many of the best managers have served an apprenticeship with their company and worked their way up, rather than being 'head hunted' from another managerial position.
I am not saying that this guarantees he would succeed. I'm not even saying that I think it would be a good appointment. Just tired of all the "needs to prove himself elsewhere" shouts.