I was thinking the same and in addition to that I already posted my idea to even integrate the merit into the activity rank
Maybe it would have been best not to create a new value for the merit but simply use the activity the same as it is used for time and activity right now.
So instead of this
The activity number is determined in this way:
time = number of two-week periods in which you've posted since your registration
activity = min(time * 14, posts)
We would have used:
activity = min(time * 14, posts,
merit)
and everyone would have gotten the same initial merit as his activity at the time of the change.
This way nobody would have been affected in his current rank by a positiv or negative direction and we would still only use activity instead of an additional counter on all accounts.