Not really sure how this weekend showed that; GSP is a completely different fighter than Griffin. First off it would happen at 185, not 205, so Silva wouldn't be as physically strong, secondly GSP can take anybody down. The whole fight comes down to GSP's takedown vs Silva's defense and striking, and GSP's top game vs Silva's guard. Nobody has a better top game in MMA than GSP other than maybe BJ, but the size advantage will come into play, and Silva has a very good guard.
I think this weekend showed exactly HOW big Silva is and how strong and powerful. He is better on his feet then GSP; faster, more accurate, more powerful, more versatile and I think his footwork is much better as well. I actually think GSP might have a hard time taking him down because he won't be able to frighten Silva with his standup in order to set up the takedown like he normally does. Then IF he does get Silva down, then what? I don't think he is strong enough to control him and Silva's ground game is top notch as well.
The Silva that fought this weekend won't be fighting GSP though, he is going to be 20 lbs lighter and weaker. If he takes him down, which I think he will, then its a battle between his top game and Silva's guard. If GSP passes guard, then he will almost certainly win. Yes Silva has a great guard, so it will be an interesting battle. I don't think Silva's guard is as good as GSP's top game, but his striking is clearly better, so it has a lot of ways it could play out.