Well... I was sure most will not even come close understanding what I am aiming at.

We (steembay) are sustainable because of donations and the upvotes people give us on each auction and our daily reports. Our service is so "ridiculous" that it relocated more SBD in the last 7 months than all minnows together. Most selfvotes serve to organize the overview of the auction process. If I wanted to use Steem as a piggy bank the system would look MUCH different and would be not effected by sadkitten anytime soon.

Cherrypicking from my dystopian forebodings (50%) doesn't change much about possible outcomes of an arbitrary (or by an algorithm) set line. I simply don't like that for reasons I tried to explain. It is a well researched fact that people tend to approach to those lines as much as it is possible. Sadkitten has the potential to become such a "rulesetter". Let's pick any number. 96% ...
If enough people are involved and invested in your project this number will become the number to tend to. (you can see this development e.g. with minimal hourly wages, taxes, even abortion just to name a few). People will see that line and "feel" that it is socially accepted to selfvote at 96%. Seen from this perspective your service can have the contrary effect than expected.