I think your ideas are very good and agree with some points you made. Especially, I support removing curation reward part and I believe this will reduce many problems we currently have, such as bot-domination and just following whales' vote.
Regarding complexity, Korean community members and I discussed about the n^2 reward calculation these days. Obviously, superlinearity is one of the most affecting factor that adds the complexity, and if we can remove Sybil issue by moderation I think linearity will meet KISS.
A sort of voting cap ($8000) was also discussed in Korean community as well, and we think it would be good if Sybil is moderated here again.
Please keep in touch (on steemit.chat?) and I am looking forward to more discussion and brainstorming.
Keep in mind that superlinearity is not there to combat the sybil issue (in fact, its what makes the sybil issue an issue in the first place. A sybil attack wouldn't make any more money than regular voting without the n^2 curve).
The purpose of the n^2 curve is to remove the incentive for self-upvoting. And it doesn't even really do that for everyone, just people with a small enough amount of SP not to be able to get a payout on self upvoted posts.
This is a problem that the founders double solved -- because both the ability to downvote and the n^2 curve are sufficient to police self upvoting. But the n^2 curve has the negative side effect of exacerbating the already very serious problem of over-concentration of SP.
Here's what i suspect happened. Ive read that originally they wanted to make a system without downvoting. To stop abusive self-upvoting, they created the n^2 curve to reward consensus. Then they realized the n^2 curve made the system vulnerable to sybil attacks, and that they needed downvoting to close the vulnerability.
What they might not have realized is that the downvoting that they adopted to address the sybil vulnerability was also sufficient, in and of itself (and in fact better suited) to combat the self-upvote vulnerability that the n^2 curve was created address.
I might be unclear on Sybil part, but I mentioned what you pointed out, especially Sybil with split accounts.
Downvoting and n^2 are all shown in the white paper. I also remember in the beginning steemit has downvote button next to upvote one, but didn't remember why it was disappeared.
IMO, n^2 system surely prevent self-upvoting but also makes people to follow whale's voting. Also given the uneven distribution of voting power, as you mentioned, it makes the game more unfair and complex.
One of the most problem of n^2 curve is helpless feeling of minnows and dolphins, which bring about less incentives to buy more SP unless it is hundreds of thousand dollars. Many people realized that buying hundreds dollars of SP never meaningfully increase their voting power. In this sense, I like @snowflake's ideas of voting cap.
Feel free to contact me @snowflake on steemit.chat