There certainly are times you need to lean on the QB to do exceptional things. Tua in the second half against Georgia in the championship game comes to mind. Heck, even Vanderbilt this year. I get the idea sometimes you have to turn to your QB and go do something special, you can't always just say we're going to control this game on the ground, or we're going to take the QB out of the equation.
But... I think you and I agree on parts of the problem but not necessarily on who to blame. I think Milroe is basically a symptom. You said earlier Bryce willed Alabama to victory in some games, but I see it as a chicken and the egg type situation. Did Alabama need Bryce's heroics because they were the only way to win, or because once they became overly reliant on QB play it became the only way to win?
The end result of where we are now though is something that basically an issue we can agree on. My mentality though is that the coaches should have been making him hand the ball off more, forcing his hand more and then if he refuses he deserves to sit. If they aren't doing that though, if they have not presented him with such an ultimatum then ultimately it becomes their failure as well.