I think merit farming should be more moderated, so it's better to report individuals who do that and let moderators check and issue a warning/punishment rather than disabling merits in a whole thread. There are many good and informational posts there so I think they shouldn't be discredited because of others.

I've seen a lot of merit farms in local boards/threads that accumulate even more merits and I haven't seen any action taken. It is probably because it would be hard to moderate every single thread and user manually so the system can't really be accurate and ideal.