First of all, I don't think the rare goods should be nerfed. The better way would be bringing other activities to parity. If the nerfing does happen nevertheless, I suggest the following method: Make it so that each player can earn merits from hauling each type of rare goods only once per weekly cycle, or only for the first 50, 24 or whatever amount of tons if you want a stronger nerf. That way, CMDRs would get some benefit from them, but it wouldn't be the main PP activity for many. Not that many would go after dozens of different rare goods every week. I also think that hauling hundreds of thousands of tons of the same rare good goes against the theme of them being rare.