Interesting opinion piece on writers and fans judgements as to whether a coach is good, bad, or indifferent. It's apparent that coaches like Klopp, Wenger, Pep, Mourinho have a big influence on the philosophies of their teams, but what about so many others? Here is the article. link
I think the article is pretty good but I'm not sure if more access to practise sessions is really helpful. You can watch the various exercises and try to draw some conclusions from them but you have to talk to coach about his ideas and goals, and pretty concrete things, not just some generalities, to get a a good picture. I doubt there are many coaches who are willing to be that open. Hah! Maybe the reason Schalke goes through so many coaches is because most training sessions are open. We just realize earlier that our coaches suck than most other fans do. Another big reason why it is so difficult to judge a coach is a high degree of chance and randomness in any football match. Bad coaches can ride lucky streaks or a run of good form and gain enough reputation to get rehired after they are fired. The opposite is also true for a good coach, who could be done in by a bad stretch. You have to give a coach a lot of time before you can judge him on the way the team doeson the pitch.