It's a bit silly to criticize (rather than change) constants that were chosen while spitballing. If 500 merits is not enough, then make it 750. If 10 unique members is a threshold that's too easy to game, then make it 15...
You've already picked up on my point here in your next post: Using numbers which are sufficiently high to make it resistant to abuse will also make it nearly useless.
I am also in general against any proposal which brings us closer to Reddit's "mob rule" upvote/downvote type system, where unpopular but factually accurate posts are often hidden from view.