The Starbuck "reveal" (Which I found to be the opposite as it was just raised questions!) bothered me in both its concept and execution.
The entire show we're told Starbuck is *sigh* The Chosen One and it turns out that means she'll be replaced by an entirely unexplained mystical angel that will lead them where the plot demands? It's just lame. There's nothing for me to chew on or think about there. "God did it!" is just... boring. I like RDM as a writer but his spiritual views are really simplistic.
When John Locke in Lost was replaced by MIB it at least had a point to it and was thought out on some level. Spirituality in NuBSG is pretty much the opposite of what I'd expect from a show. Endless strings of visions and divine intervention that rid the show of consequence and are never explained or cohesively put together.
I went with the notion that it was Starbuck the whole time, she was just different. She wasn't the chosen one, she just had a part to play. It tied into Colonial religious belief of "all this has happened before and all this will happen again", Leoben who introduced the concept of her being a "chosen one" as you want to call it, mentioned that everyone has a part to play in life. Starbuck's role was to lead them to Earth. Part of that role included her dying and returning. She had to die in order to set up a chain of events that lead to her remembering "All Along The Watchtower" and to figure out that it was the jump coordinates to Earth. "God did it" isn't the answer, Starbuck got them to Earth, God only brought her back to life. Saying otherwise is a gross misinterpretation of what clearly happened on screen.