Only real new members (who are eagerly to learn) will be motivated by merit system. Account farmers hate it certainly ^^
Newcomers also have long-term motivation to learn at the forum.
Of course, merit system can not entirely changed the forum by itself. The system need cooperation of the forum members, campaign managers. As you saw, there are lots of topics on merit abusers and several campaigns ask merits to join.
Even though the merit system was introduced, I always see repeated and redundant posts.