OoTP seemed to imply that Draco was loyal to his father but afraid of Voldemort (that scene with Harry at the end, where Snape interrupts them). That leaves plenty of potential.

As for the "Hogwarts is no longer a refuge" thing, I saw that as part of Harry growing up. As with Buffy, I've always seen a lot of what goes on in Harry's life as extreme versions of what kids his age always go through, and now that he's almost sixteen, he's going to be looking at his protective authority figures and seeing their flaws, and being angry and resentful, and learning to see adults as real, complicated people rather than idealizing them, and all that stuff. I thought this book did a fantastic job of taking him onto all that adolescent territory.