First off, why does this have to be a new thread? Cant you ask this question in the announcement thread, or maybe read it and see if those concerns are already addressed?
People with the highest ability to give merit are the sources, theymos has selected those sources (35, undisclosed).
If they dont use the merit system as intended, meaning dont give out merit to people making good posts, theymos would have made a bad selection.
Upon discovering this, he most likely will replace a source misbehaving with someone he sees fitting better.
I feel that 35 sources are not enough to do this task efficiently (I may be wrong, you guys know more than me).
Bitcointalk community is huge by members, by threads, by posts. It is kinda challenging for those 35 sources I believe.
However, I also believe that the merit system is just introduced and it is right to say that it is under observation and it will get improve whenever it is necessary.
Keep up the good work.