I look at this situation the way I look at teaching. There are two kind of teachers, technical teachers and reflecting teachers. Coaches are more or less teachers, so the same goes for them.
A technical coach goes with what's tried-and-true and doesn't rock the boat. You know it's worked in the past, so why change it? A reflective coach looks at every game and thinks "What can I do to make thing different?" What worked, what didn't, and how do you learn from it? Being technical minimizes the risk, but being reflective increases possibilities.
The problem is that your choice between the two doesn't really have to do with training, experience, or whatever else, but deeply-rooted attitudes towards life in general. I'm worried that, at the end of the day, Corbin is a technical guy. That he lacks the belief and confidence that trying new things may be disastrous, but may also yield amazing results. You could see so many times this season how he lacked confidence to be bold. Even worse, he doesn't even necessarily have faith in his technical approach(like Coach did for two decades), but is open to outside pressure. He wilted before the vets most of the season, only to finally snap at Bell late. He refused to start a taller lineup against the Spurs until well into the series. When he does make adjustments, you get a strong sense that it's not because he actually looked back and decided that a new approach is the way to go, but that it was a "Fine, let's try it the way everyone is suggesting" kind of a thing, without a real commitment to it.
This is why I haven't liked Corbin all along, this is why I want him replaced, and this is why I worry that if we don't, he'll still have the exact same habits 5 years from now.