I believe that, yes, the friend req limit will help to curb the RMT activity. But it will only do this for friend req related RMT activity when the larger and more consistent issue seems to be with /tells. In fact, I'd wager that with the enforcement of /tell activity being as lax as it is all we're going to see is the RMT sellers who do use friend reqs just switching to /tell, which will at best just shift the problem if not make things even worse.