I have read this post thrice now, to make sure I have created a picture in my head with no holes.
I agree with you mostly, and disagree with just 1 thing you mentioned

deinventivize powerdown

I dont disagree per se, but I do believe there ccould be a better model to discourage powerdown

But that's not what I'm here to talk about. I hope more people join in on this and leave their feedback. I might have to read this a couple times more and brainstorm for like 5 days before I can give a solid feedback and show my standpoint; whereas someone else could do the same in 10 minutes of reading this.
For now, to me, it seems like you have got an unsolved Rubiks cube in your hands, with a little bit of tweaking from each side and we will have a beautiful comepleted piece.