I did a few research about voting methods and the best seems to be the Schulze method [1]. After reading its process I just saw that it is in fact widely used in Open Source projects!
Lots of US states use ballot measures. They don't seem particularly hard to game in the same way elections can be gamed, especially when there are too many ballot measures for a typical citizen to filter through in detail.
[1] https://en.wikipedia.org/wiki/Schulze_method#cite_note-Frenc...