The merit system is one of the best updates here on bitcointalk as of now. People used to be able to spam their way up the ladder easily; they could even reach Hero Member status without even knowing much. This significantly lower the amount of spammers that could join campaigns, which is very very good in my opinion.
In a way its good for forum but not so good for new users and for sure even worse for spammers.
So in the end, i would summarize merit system is good one. More advantages.
If merit system can be improved? For sure, just by advertising how it works and that you can give merit to others when u like their posts.