History has shown in the case of bitshares that the refund standard was set very high, and in such a way that it easily weeded out questionable proposals.
In general, a lot of your arguments make assumptions that I find very questionable. For example, I think you're flat out wrong on the support level of witnesses for 50% curation (along with some of the other proposed changes to curation). In my opinion, I think a strong majority were in favor of the idea, and the primary blocking issue was just finding someone willing to do the work for free when Steemit devs didn't show a lot of interest in taking on the task themselves.