Aldo is a baddddd matchup for Pettis. I've still never figured out if Pettis had his spirit broken or if he has no heart.. either way, I see Aldo destroying him. Aldo is a top 5 ATG.
Prime Silva vs GSP is a toss up... two of the best ever in MMA. Top 5 GOAT's. GSP is the most complete fighter known to man that can adjust to any situation. If he knows what's best though, he would wrestle Silva. Silva was just too flashy with his standup back then. IDRK if it's fair to pick, because, I like both of them, but I would say GSP grinds out a decision using his wrestling.
Healthy Sea level Cain beats Jon Jones. out of anyone, ever, Cain is the man I could see dethroning Jones. I've always said Cain and a Prime Anderson Silva have the absolute best chance out of anyone to beat him. more so Cain than Silva, but still. Cain hits way harder than DC, and has a relentless type of pressure that just folds people mentally. I would say Cain by UD probably, just given that Jones has an iron chin (doesn't mean he can't be finished though)