Sorry to say but PD just lost alot of its presence on this forum, which I think is bad, If newbies come in they will see other sigs now, if he cuts out half of the seniors you can say good bye to PD presence here.
That's a decision you've to make. At the other side, personally I would click URLs in signatures of Senior Members faster rather than URLs in signatures of members. And hey, this is going to be cheaper for Stunna. Maybe the "lost of attention" and the thereby "lost of income" will be compensated be the money Stunna safes on not accepting < senior members anymore.
I'm sure Stunna is wise enough to check out for himself what's the best for him and Primedice. I do think that the new referalURL system brings in a lot of attention too. Maybe you should promote your referalURL on these and other forums, see the first post of this topic.