I think the willpower question in recovery is very interesting. I get that it's a very powerful concept if you believe in an AA higher power, and so you have this very deep emotional process of letting go of your will and trusting in God. But I'm not sure if it's as important in an agnostic/atheist context. I spent a lot of time wrestling with this when I was in rehab, because the only religious belief that I put in the 100% category is that if there is any kind of higher something, it doesn't have a "will" for individuals. That being the case, I'm not trusting in anyone else's will, it has to be mine. I never really found a way around it. The closest I got was to link giving up the will to Buddhist non-attachment.
I guess maybe it is important to distinguish abstinence/sobriety from refusal/willpower. There are definitely more mechanisms involved than just saying no. But at the end of the day I'm not certain that I can't attribute my sobriety at least in part to my will?