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? You've earned 1096 Merits, so your voting power is 3.0398. O_e_l_e_o earned 12992 Merit, so his voting power is 4.1137. A user with the A user with the minimum of 50 earned Merits, gets voting power 1.6990. This way, the increase in voting power is only very small so votes from newer members don't become worthless.