First of all, I want to thank Ned for putting these ideas out for community feedback. One of the reasons I disagreed so strongly with the 5 vote idea (in another recent proposal) was that it was being included already in a pending release. Making us an offer we can't refuse is a shitty way to run a community; asking for community feedback is much better. Kudos to you for that.
However, I find it rather disingenuous for you to mega-upvote the first comment that fully agrees with your ideas in this post, since they are meant to provoke an open discussion. (EDIT: You downsized it, which I think is appropriate.)
I think your first idea may have some merit; I need to learn about it more. Curation seems to be working well, from what I can see. Project Curie is discovering and rescuing many worthy authors from total obscurity. I think the site is trending in the right direction with more intensive efforts to find and reward undiscovered and deserving posters.
Maybe the curation pool you describe would help. If so, I would like to learn more.
I do not like the power down penalty, mostly for the reasons that @smooth has discussed in his responses. Not only would it hurt large accounts' ability to curate, but it also would freeze Steemit's redistribution. As @smooth has described, allowing big whale accounts to sell their Steem is really the most efficient means of redistributing Steem to new holders. I might be OK with some movement in the direction of perhaps some "fee" for Powering Down often (if this was needed to address some problem), but I think that penalizing Powering Down in any severe way will hurt Steemit by making redistribution and curation nearly impossible.
Can't we work on developing these other pillars of the ecosystem to help create more demand for Steem, rather than trying to control its use?