Feature One - Linear Voting Curve
Fully agree to this. Interested to see after HF17 and whales start to upvote again, what the effects will be on the minnows and their activities. Even with the linear curve, more rewards will be pulled more to the whales side then the situation created currently where whales do not vote at all hence all the power and rewards distribution in the hands of dolphins and minnows.
Feature Two - Tiered Steem Dollar Interest rates based on Steem Power holdings
As a model this seems to me an interesting approach. It 'forced' people to increase their SP when they want to get some interest. You can also argue to remove SBD completely and give interest on SP itself, with a tiered model as well. In addition, you could think of a model in which all posts are always power up for 100%, ie rewards are always in SP, not in Steem and/or SBD anymore. This makes sure that quick cash outs are prevented. The 13 weeks for powering down maybe increased again to eg 6 months, to make sure that the people on this platform are into Steemit for the longer run and not for the quick financial wins. Maybe an experiment can be executed in which everyone who does not power up his/her posts with 100% gets downvotes from the whales, ie no payout.