Here's an idea: what if you paid people for unspent voting power? Right now, when an account's voting power is at 100%, they have this trickle of voting power that's just going to waste. If you paid them for it (the network "buying back" the potential curation rewards they could be earning), each person would be able to choose whether they wanted to earn curation or just sit there and let their balance grow.
I haven't thought through it at all, but it's a quick-and-dirty way to let whales individually opt-in to something like your 250Mvest proposal. AND, because of the sub-linearity of curation rewards, large accounts would see a bigger bang for their buck by not voting than smaller accounts.
@smooth actually brought up this exact idea in @snowflake's post. It is a good idea and I'm not opposed.
Two arguments against it are:
Yeah, that's a fair point. Even if the rewards for curation would easily be higher than the rewards for sitting, it would easily feel like an incentive not to vote.
That's true.
If the rewards for curation are higher everyone would curate.
Good points. The problem I see with this proposal too is that minnows's influence wouldn't be stable. If their influence goes up and down all the time they would be confused and might not buy as much steem power as they would otherwise.
That will be true regardless though. The amount that an individuals vote is worth is always dependent on the amount and way the rest of the active voting stake is being used.