Good idea
[at least than nothing], but you only talk about the positive impact you expect from implementing the idea but you don't explain what the negative impact will be on the forum and users. Do you also think the two impacts may arise simultaneously?
The benefits and improvements this will add to the forum is endless, but I just can't mention all, but like I said earlier, it's a crazy idea which not many people would agree to, most especially, those that have hard time earning merits because of lack of quality posts.
I hope you don't take this too seriously since you've thought about it, so on this I'm in opposition to your idea. But in fact your idea didn't get much approval from some of the better users than me. See first, second and third responses. But I wonder, does the report posts to moderator feature not help you reduce spammers and prevent them from being ranked?