This is actually a great thing that you have reacted so fast to the number of new accounts increasing. Could that be due to bounties as well as they are getting more and more popular and this forum is the main source of it all?
From that perspective, it's a good thing that it's harder to rank up as it will filter the members who are hard working from the competition that spams and doesn't add any value at all. I really believe bounties are the future of work, giving opportunities to people from all over the world to make extra income.
Perhaps it would be interesting to see which sections get the most attention when it comes to giving and receiving merit?
Also, have you considered that a "black market" might emerge... people buying and selling merits OTC?

It sounds silly but who knows...