Another idea would be the weight of votes. In other words, the vote of a Legendary was worth more than a Member.
A bit of what happens in the voting of sports associations, that those who have been a member for the longest time are entitled to more votes than new members.
If you're going to adjust voting power, why not give each vote the power of the log of the earned Merits?
Very interesting idea. Taking earned Merit into consideration and adjust votes according to log earned Merit, achievements (ranks) would be taken into consideration while lower ranks could still participate.