I don't want to get too much in the weeds; however, probably, what you are suggesting would be a bit of an improvement over the status quo, but really there seems to be a broader interest in bitcoin and rights and stakeholding beyond current actual coin holders. 

I mean we have future coin holders, we have past coin holders, we have people who invest in bitcoin through product, services and possibly in other ways such as alt coin contributions that may be absorbed into bitcoin but may not currently hold bitcoins. 

There may be ways to give weighted value to a broader segment of the various bitcoin stake holders beyond actual coin holders even if they do not have actual coins (or many coins) at the moment of an actual poll/vote.