Transparency is great in public institutions that spend our tax money. In communities like this, we just need a chieftain to handle our disputes fairly and keep us all from going nuts every so often. Those of us who have been coming back for years already know that you do that, or at least try your best to be fair and open and neutral.
I doubt you could keep everyone happy by releasing a log of moderator actions. People complain now, but look at ArbCom on Wikipedia, which makes all the decisions in public, and there are websites devoted to trashing the process there. And if you're not making people happier, nor making their interactions here more pleasant or informative, what is the goal again?
Plus, it's not just moderators getting a chance to make mistakes, it's also the users. I don't want to end up in a log somewhere for my terrible posts. You've told me to improve before, and I did. At least I've tried to. Admittedly my posts haven't been high quality lately. Anyway, the more formalized the process becomes, the less human we're all allowed to be. That can be good or bad, but I think in this case it's been good. Most of the reactions to OP tend to think that privacy is valuable sometimes.
I could be wrong, of course. Do what you think is best for us. That's why we keep coming back.
I completely agree about wanting to stay on the human side of formal vs. human.