I agree on this point, the only real pity is that the merit system has not been implemented already a year ago, before the demographic explosion of the the alts accounts - I guess for reasons of bounties. To procrastinate further the adoption of this necessary measure could have been fatal for the forum.
On the other side, if I may joke on that, merit the worse thing that happened to old high ranked users who were about to rank up

The admin made some adjustments for such unlucky members.
Only for Hero Members with over 750 activty, my dear, and if you don't believe me look at my activity and compare it with my rank

Jokes apart, theymos has in fact mentioned once that also lower high ranking members who were about to grow in rank at the moment of the change of rules should eventually be given the missing merits after a rewiew of their posting history, or something like that, but I didn't see any traces on the forum of this having ever happened, at least no-one has mentioned cases in this meta area of the forum.