1. The process of sending merit seems a bit annoying. You've to go through another web-page and select number of merit to be sent and then send it. IMO, it'd be better if it could be sent just by clicking "+Merit" button right within the thread.
This will increase the chance of double sending merits. I think its good idea if there is a confirmation first before sending.
2. It'd be much better if you guys allow only one merit by the merit-sender per post. This will reduce fake-merit-exchange or fake-merit-giving. There're people sending tens of their merits to a single post which clearly seems like something fishy.
For me it is not suspicious if they send 10 to a high quality content some sends 20 but if its reasonable I dont find it suspicious, and if they change the rules of merit system to this maybe we cant identify now who abuses the system.