Man i dont like when Dana does this. GSP has said numerous times that he does not want that fight. It is one thing trying to push someone in to a fight in his own weight class if he is resistant. Its completely different when the guy has his own path for his career and it is competing at 170 not going up to face the p4p best fighter. You dont try and force that on someone unless both guys want it. And in that case it wouldnt be forced.
I think GSP's hesitation had more to do with moving up to 185 and being able to pack on enough muscle to not be at a strength disadvantage. No point fighting the "BJ Penn 185" with a paunch.
What they've been bandying about lately though is a catchweight fight at 180 or 178, and that I think would keep things more fair. Silva would either have to lose some muscle, or come in much more drained from a major weight cut, giving GSP an advantage in spite of his relative smaller size.
I think GSP would be more open to that, based on what he's said. He's always given bulking up as the main reason.