I think Scott's very disciplined and and lives by a strict code, which makes him come across as a goody two-shoes, but a lot of writers have explored that it's more of a defense mechanism against a lot of inner turmoil. He had an intensely chaotic and traumatic childhood, a life and powers that felt totally out of control until Xavier gave him a father figure, a purpose and a way to take control of his powers and his life. Of course he's going to be a little intense in his dedication to Xavier's dream.
But Scott's "boy scout" persona is a defense mechanism. He's messed up inside. He's constantly overcompensating for his fear of losing control, and not just of his powers.
I think he's actually a really interesting, complex and dysfunctional character. I feel like people who view the character as some vanilla goody two-shoes don't really get the character. There's a lot of damage and dark emotions that his idealism and discipline are covering up.