The main thing that managers need to continue to prove is that they are making rational decisions, and that more often than not, they are the right decisions. This shows that they are level headed, and have the knowledge to run a team at the highest level.
It always worries me when we see an Everton team chopping and changing every week, with different formations and personnel. There is no doubt that our best run of form last season was down to sticking with what worked well, which was the same way of playing, same formation, and nearly the same starting XI. Koeman lost the job because he did the exact opposite. It seems Martinez didn't know how to turn things around, which ultimately came down to poor decisions in terms of tactics and personnel.
Silva looks like he is a man that will adapt to any given situation, which is a fantastic attribute to have, and one which his predecessors lacked. No matter how this season turns out, I think he deserves huge credit for turning it around the way he did, and it bodes well for him in the future.