the experiment partially worked only because the economy was at its infancy and people weren't bothered/sophisticated in trying to get around it

these days, with delegation and whatnot, it's trivially easy to split your stake under multiple accounts and circumvent the measures you suggested

i haven't seen a better set of ideas than higher curation, moderate free downvotes and slight superlinear. I can't think of any obvious ways it can be abused. It does mean we have to accept some of the negatives that come with it like less author rewards (which is a big deal assuming now the econ works and authors aren't just the stakeholders but good content creators), higher toxicity through more downvotes, and somewhat inequality through superlinear.

the idea is to minimize their negative effects while still having enough of these measures to get a working economy.