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.
Don't you feel this will encourage merit abuse? For those who achieved the ranks by earning merits, for them it's not a hard task to earn one merit for ten posts. But definitely spammers will exchange merits between them. So the idea still will benefitspammers. Real contributors don't have any issues at all. On the other hand, forcing merits for each ten posts really looks like a stupid idea. Sometimes even a good contributor doesn't receive merits in their ten posts. But maybe in the next post they will receive 10 merits. So forcing isn't an ideal idea at all.
The current merit system is working well. Still a lot of people struggling to achieve their ranks. Even some good posts have been underestimated and not receiving merits unless someone points it out. Because it doesn't possibly merit all the good posts by merit sources, they might miss a lot of things. However, the idea isn't much useful at all. Merit is a reward of your post, not a matter of force.