The way the account rankings increased in the old days was straight. Any user could become a room member and a legendary member by fulfilling the requirements of the post. Then, a minor update came, and the rank was increased based on the activity with the post. This was also not very difficult for the forum at that time. Then came the countdown of merit with activity. This was a good time for the forum accounts to move towards the ranking. Combining activity with merit was a very good thing for the forum, which complicated things with the growth of beautiful scammers, which continues to this day.
The idea here is that there's a new term called "carry" that will slowly de-rank you if you keep posting/doing things that nobody appreciates. That is, you can't just apply yourself to the task of achieving a given rank, you also have to apply yourself to the task of maintaining it. Just like your "merit" is a >=0 balance based on logged events, your "carry" is also a >=0 balance based on logged events. There's a more general version of this idea where different forum actions attract different amounts of "carry", but, the simple version that I think should be experimented with initially is just one where there's a single type of system-generated "carry transaction": Whenever you make a new post, your balance goes up by 0.1. In effect, you'll need to earn at least 1 merit for every 10 posts you write (on average) if you wish to prevent your account from slowly drifting toward a lower rank. And you'll need to get beyond a 0.1 merit-to-post ratio if you're aiming to increase your rank.
Here, you want to add a new "carry" with merit that will control the system of a user's rank going up and down. This idea of yours will generate an idea about the disability of the users of the forum and the quality of posts they are making. You have explained that the "carry" system will show the merit number as a reduction. Although your idea is nice, I could not agree with it because the number of users in the forum is not very high. If such a system is introduced, the number of users in the forum will be reduced even more. If someone cannot earn a merit in every ten posts, then the busyness of their account will decrease. In reality, if a user has made ten posts but cannot earn merit, their "carry" will increase, indicating the reduction in merit. In reality, this will have an impactful signature. In reality, this is effective; the number of spammers will be completely zero, and the number of users in the forum will decrease, which is natural. I believe the current merit system in operation is sufficient for this forum.
(*) It would slowly decay "airdropped" merits that either belong to accounts that have now changed hands or that were awarded in the first place to users that would have been unable to earn those merits organically. Basically, I'm thinking of accounts like
mich (that account has only managed to earn 36 merits over
thousands of posts, but it has the rank of "Legendary" and wears a paid signature). If an adjustment like what I'm proposing were put in place, then the person behind that account would have to re-think their whole approach to the forum (if they wanted to keep spamming their signature, that is).
Yes, it will erode airdrop merits, and accounts that have changed hands will no longer be able to grow. However, it would be great if all legendary rank accounts were progressing as they should be, clearly visible. Signature spammers can be identified and removed.
(*) It would make it harder to buy/sell accounts. As in, sure, you could buy a "Legendary" account, but if you're going to just post mindlessly with it to make money, then eventually the "merit" that came with the account will be undone by the "carry" that accumulates each time you make a post. (And then, hopefully, the account will be considered worthless and can stop being traded.)
(*) It would make it harder to buy/sell merit. As in, sure, you could cheat by buying some, but, you'll likely have to do that repeatedly, because, as with the previous point, if you're just going to post mindlessly, then eventually the "merit" you bought will be undone by the "carry" that accumulates each time you make a post.
I agree that accounts that are bought and sold will no longer be able to move forward. When these accounts see that it is complicated to move forward in this forum, no one will buy them, and the buying and selling of accounts on the forum will stop.
(*) It would encourage more mindful posting in general, I think. A small "cost" risked by the poster each time they submit something encourages them to ask "Do I really need to be posting this? Do I really think that people might appreciate it? Or is this likely to be a post that only contributes to me losing rank?".
If this practice is introduced, then after writing a post, a user will think about what it will look like if they make this post. Nowadays, people write posts very quickly to fulfill the requirements of the signature campaign, but do not care about the quality of the post or how much that post can be appreciated in the forum. The "carry" of accounts that meet such requirements will increase, and those accounts will lose their position by decreasing their rank. If this practice is implemented, the poster should try to write quality posts with great care before and after writing a post. This will maintain the balance of the forum, and many good-quality posts will be noticed.