Nice logical approach here, I can really see the argument for getting rid of SBDs now that we've functioned without them for so long. Might be a bit of a shock to short term Steem price converting them all though.

While I like your thinking behind the automatic 'powering up without powering up' option as it's simple, I don't think it's necessary - I think maybe changing the terms like @therealwolf and others have suggested to 'staking' makes more sense, but I don't really conceive of staked steem (let's start calling it that!) as a different type of token to liquid steem.

But the idea of fewer tokens/ less complexity is definitely something that I think would help popularise Steem.

I guess communities can make things as complex as they like!