Merit system worked for a while until it didn't.
I don't know the state of things before this system, but it is clear that it does not work at all. Almost all posts everywhere I go are junk, very few are non generic garbage. If a system like this was working, over time most posts would converge on the quality of d5000's posts. As people genuinely try to do research, learn and improve their content then the average post quality must continue to rise consistently. Not really. To achieve this kind of scale, the cycle of new users would need to be non-constant, there would be no alt accounts, and some of the good posters would need to stay.
Like any system, it is infallible against abuse. Unfortunately, abuses do occur. But for me, the problem isn't who receives, but who gives. In turn, if someone is free to give merits to whomever they want, even if I don't agree with those choices, that's their right.
actually has a real solution unlike the problem that is described in the title of this thread.
While I would not mind individual improvements such as the proposed in the OP, I agree with you. There is very bad merit farming and cycling in local sections that this would not do too much. Whenever I see an user with more merit than is warranted by his post quality, I quickly find that he has earned them in local sections for short or generic posts. 
This is also very subjective. Someone can write a very good post and receive a lot of merits, and then write 30 weak posts and receive zero merits.
Anyway, I see this conversation as being more about creating rules for assigning merits than anything else. It seems people have forgotten that there's always been a lot of freedom on the forum, and they want to impose similar rules—unfairly—to those that exist offline.