Yeah, "graduation" seems to be a bit off-key. It's promotion by dead man's boots, and even if Dick wanted to be Batman at some point, I doubt he'd want it this way.
That said, I think a reluctant Batman is an interesting subject. Batman's pretty much defined by a total focus on "the mission"; having a character do something they'd rather not is only a mistake if their prior views are glossed over and forgotten. Like Didio says, change is good, but only if it's change that makes sense - "You liked it when he became Nightwing, so you'll like it when he's Batman" seems to be setting up something of a well-poisoning, but i'm probably just paranoid.