The r/achipelago subreddit is quite small but exists for hobbyists to share designs for alternative political systems and to consider the effects the alternatives would have. Most of what's there right now is about electoral systems rather than full institutional structures. Some posts include links to resources, such as one of my favorites, The Electoral System Design Handbook, which describes case studies of several countries and the typical good and bad effects of different design decisions.

"Ideal governance" depends on what ideals you're aiming for, of course. There have been proposed improvements to futarchy such as this one, which picks utilitarianism as its explicit ideal.  An explicitly virtue theorist option could be to modernize Plato's Republic instead. Granted, these are extreme examples. For more sober-minded investigation into ideal governance, you'd of course want to start with criteria that are well-defined and pragmatic, rather than broad philosophical or ideological traditions.

Yes. Page 287 of the paper affirms your interpretation: "REMORSE does not exploit suckers, i.e. AllC players, whereas PAVLOV does."

The OP has a mistake:

Remorse is more aggressive; unlike cTFT, it can attack cooperators

Neither Remorse nor cTFT will attack cooperators.

If Pavlov accidentally defects against TFTWF, the result is

D/C -> D/C -> D/D -> C/D -> D/D -> C/C,

Can you explain this sequence? I'm puzzled by it as it doesn't follow the definitions that I know about. My understanding of TFTWF is that it is "Tit for Tat with a small randomised possibility of forgiving a defaulter by cooperating anyway." What seems to be happening in the above sequence is Pavlov on the left and, on the right, TFT with a delay of 1.

in Critch's framework, agents bet their voting stake rather than money! The more bets you win, the more control you have over the system; the more bets you lose, the less your preferences will be taken into account.

If I may be a one-note piano (as it's all I've talked about lately on LW), this sounds extremely similar to the "ophelimist democracy" I was pushing. I've since streamlined the design and will try to publish a functional tool for it online next year, and then aim to get some small organizations to test it out.

In brief, the goal was to design a voting system with a feedback loop to keep it utilitarian in the sense you've discussed above, but also utilitarian in the Bentham/Sidgwick sense. So that you don't have to read the linked blog post, the basic steps in voting in an organization run on "ophelimist democracy" are as follows, with the parts that sound like Critch's framework in italics:

1. Propose goals.

2. Vote on the goals/values and use the results to determine the relative value of each goal.

3. Propose policy ideas.

4. Bet on how well each policy will satisfy each goal.

5. Every bet is also automatically turned into a vote. (This is used to evade collusive betting.)

6. The policy with highest vote total * weighted bet value is enacted.

7. People are periodically polled regarding how satisfied they are with the goals, and the results are used to properly assign weights to people's bets.

score voting is immune to the Gibbard-Satterthwaite theorem

I was basing this off the description in Wikipedia; please correct that entry if you think I was in error. As of this time it still explicitly states, "While the scope of this theorem is limited to ordinal voting, Gibbard's theorem is more general, in that it deals with processes of collective decision that may not be ordinal: for example, voting systems where voters assign grades to candidates."

any proportional method is subject to free riding strategy. And since this system is designed to be proportional across time as well as seats, free riding strategy would be absolutely pervasive, and I suspect it would take the form of deliberately voting for the craziest possible option.

What does that mean? If being the "craziest possible option" means it gets selected as the most preferred option regardless and has sharply bad outcomes that you secretly knew would happen, then having voted for it, you're strictly worse off in future voting power than if you had voted against it. Alternatively, if it means that very few other voters vote for that option, then that option definitionally isn't going to win, and so there is strictly nothing to gain in future voting power from having voted for it. So on the contrary, honest voting, as a strategy, dominates either interpretation of your suggested variant of a free rider strategy.

it's a nonstarter politically

This is rich irony coming from Jameson Quinn himself. :D In any case, your comment here is certainly appreciated due to your expertise, even though I currently believe the comment was factually in error on both substantive points.

Regarding exploitability by well-funded and well-connected entities - I'm not sure how to tell without an empirical test. My understanding is that research into funding of electoral campaigns doesn't show the funding as having any effect on vote totals. If that is accurate, then I'd expect it's still true under alternate voting methods.

Fully agreed - the intention is to start with small-scale clubs and parts of private organizations that are open to experimenting.

increased voting power given to those whose bills are not passed risks giving undue power to stupid or inhumane voters.

True. Equalizing the influence of all parties (over the long term at least) doesn't just risk giving such people power; it outright does give them power. At the time of the design, I justified it on the grounds that (1) it forces either compromise or power-sharing, (2) I haven't found a good way to technocratically distinguish humane-but-dumb voters from inhumane-but-smart ones, or rightly-reviled inhumane minorities from wrongly-reviled humane minorities, and (3) the worry that if a group's interests are excluded, then they have no stake in the system, and so they have reason to fight against the system in a costly way. Do any alternatives come to your mind?

Dishonest forecasting, especially predicting poor results to try to kill a bill, remains tempting, especially for voters with one or two pet issues.

Indeed. I spent a great deal of time and effort investigating this for possible solutions. Haven't found any yet, though. It's the only attack vector that I know for sure would work.

While giving direct power to the people might help avoid much of the associated corruption and wasteful signalling, it risks giving increased weight to people without the requisite knowledge and intelligence to make good policy.

I may have been unduly influenced by my anarchist youth: I'm more worried about the negative effects of concentrating power than about the negative effects of distributing it. Is there any objective way to compare those effects, however, that isn't quite similar to how Ophelimo tries to maximize public satisfaction with their own goals?

Thanks for your thoughts. Your questions are quite valid but I'm inclined to punt on them, as you'll see:

For #3, it depends on the group. If a government were to use it, they could provide access via terminals in public libraries, schools, and other government facilities. If a private group were to use it, they'd probably just exclude the poor.

For #4, 6, 7, 8: It's intended for use in any democratic organization for the equivalent of ordinary legislation and bylaws, but not intended to replace their constitutions or founding documents. If there are some laws/bylaws that the group doesn't have authority to make or change (like on citizenship/membership), they would need a separate method of striking those down.

For #5, if the data is lost, they start afresh. They'd lose any prediction scores they'd gained, but if voters can repeat their good predictions, the problem is mitigated, and if they can't repeat their good predictions, they don't deserve their old scores.

I justify "punting" because the app is intended to be customized by many clubs and organizations. It doesn't feel like that's merely handwaving the hard parts, but perhaps it is.