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.
I don't think encouraging a user to earn 1 merit for every 10 posts is too much to ask.
I would agree in principle but 1 merit for every 10 posts is outrageous and certainly demotivating most of new comers (low rank members). IMO, 1 merit per 50 posts (even 100)
would be fair and more compatible.
Just my 2 cents, you guys know much more than I do, of course.