HW - I think Werdum poses more of a threat to Cain than JDS for the simple fact that he is a much better grappler. Though I think Cains cardio will wear Werdum down as the fight goes on.
LHW - I think Machida has the tools to beat Jones, though I think Hendo is more of a difficult match up for Jones based off of his right hand, solid chin, and wrestling abilities.
MW - Weidman is the clear choice because of his style and talents in certain areas. Hector gives Silva a threat because of his power and grappling ability, but theres a a gap with level of skill on the feet (there is for most anyways) as Hector has only a few tools on the feet. Jacare is also right there for me because of his grappling ability, whether or not he could survive the time between standing and taking it to the ground is beyond me. Nut Jacare still has time to improve before a fight.
WW - My first choice is Maia because he's looked amazing thus far and if he pressures GSP like he did Fitch than he causes problems, but if he cannot get GSP to the ground then he's in for either a long night of being smashed of a quick night. Then there is Hendricks, he has the wrestling ability to prevent GSP from getting top control and has a good chance of taking GSP down if he isn't stupid about when he shoots. Also he has amazing power, so if he can connect his power plus GSP chin then I say good night GSP. others would be Rory if they fight simply because he's a scary dude. And Askren would give GSP troubles if he were to ever sign with the UFC. Also there are a few dark horse choices, but a few may be a little biased lol. John why do you say Siyar? That is an interesting choice
LW - I am probably the only guy who thinks this but I'm going with Gilbert, he has good hands, and has speed to go with it. His wrestling ability gives Bendo troubles for the simple fact that he will use it more effectively than other have in the past. Plus he has good cardio. second choice would be Pettis if he stays at LW for clear reasons. Then I could see Maynard giving him troubles if he improves his timing. Future guys are Khabib
FW - Pettis is probably number one based on his striking ability, and power. Though it'll be interesting to see how he manages the cut, both him and Aldo may gas early on. My next choice would be KZ because of how aggressive he is, power he has and submission ability. Not to mention he has a great chin (though people have stated he doesn't because Roop KO'd him, but lets be real that was a good kick). I also think Siver makes a interesting match up and threat.
BW - Barao for Cruz, and Wineland for both. Wineland is getting better with every fight. If Fernandes signs with the UFC then I believe he will be future champion. couple guys who are future threats I believe are Erik Perez and Kyung Ho Kang.
Fly - Benavidez or McCall ( if he fought with a better gameplan) or maybe Jussier if he gets the fight to the ground
Viva la Portugal!!!