If this is what you're looking for, why don't you just divide Merit by Posts? Add one to give Newbies an unbiased chance, so:
WoP
2.0 = (Merit
earned + 1) / Posts. That would give:
satoshi: 2.10
theymos: 0.33
LoyceV: 0.17
soniclord: 0.00
The drawback is that old posts may be good, but didn't get merited because they're old. Over time, this will become less important.
Best way might use the formula like (Earned Merit+1)/ (Activity gathered after Jan 24 +1) but I guess it will be difficult to calculate the activity generated by user after Jan 24 due to concept of potential activity.
Concept of number of post created after Jan 24 will fix the calculation for everyone.
(Earned Merit+1)/ (No. of post created after Jan 24 +1)