Why not put some upper cap for merits for each and every post ? I mean one post may have only some certain amount of merits.
Why should we limit it? If someone spends hours writing or maintaining a thread then people should be able to merit it how they see fit. If people think a post or thread is worth a thousand merits then let them merit it so. It always blows my mind how many threads people are going to create complaining about merit just to try get some themselves or assure others don't get as much as they should.
Yes, big people do get easy merits due to their fame or big people's posts get more attentions hence more merits.
Or maybe they get them for writing helpful. Informative posts. People should try it themselves. You never know, you might get some merit.