In summary, Green Zone will be removed and Merit Rank will be introduced.
At this point I agree with @cryptofrka this element should be added sparingly.
This is part that bothers me as well. I am trying to wrap my head about the fact that more and more campaigns on forum are going towards merit route. I really don't see the merit in using merit as metric to evaluate posters

It is really skewed way to look at things since getting them in some parts of forum is so much easier than in other parts. It is also very subjective metric and this trend will lead to increased merit farming with time.
As a campaign manager myself I am wondering if I am missing something, but as it stands I don't think I will ever want to implement that metric, especially for the people whose posts I am reading every week. College degree and great CV will only get you the job in real life, then you have to prove yourself. Once when you are in the company only your results should be the element that gets rewarded. That was really nicely handled so far with that bonus for best posters. I would love to hear your reasoning behind this change Royse. If I were looking at something like this I would rather use "Most recognized" metric on bpip, it at least evaluates more factors and not just merits. I know I will now look like a hypocrite since that one is obviously the best for myself but that is my honest opinion and I am not doing that bad on "merit only" front.
Regarding actual question and amount of posts that will be paid I don't have strong opinion. I am now paid for 25 and I am writing about 35 while being very busy in real life. That will probably rise to my standard 45 when workload drops to normal no matter how many posts I am paid for.