I would not compare Dan and Bisping.
Dan had iron chin, Bisping had average.
Dan was a wrassler turned into brawler, Bisping was textbook striker with excellent tdd and cardio.
Dan was a multiple champ, Bisping was not.
Bisping hit the jackpot really, two lucky performances against washed out AS and Luke. Bisping was in very bad shape, it took a lot of luck to finally get there.
But, Sonnen had terrible time trying to take down Bisping, I doubt GSP would hold him down. Hell, GSP even had trouble holding down granpa Bisping.
ALso physically Bisping looked like shit, I mean, no visible muscle anymore, old age and usada killed him. And even that old Bisping managed to turn the tide against GSP.
GSP's corner really saved the day with their advice mid rounds on when to throw that punch that caught Bisping off guard and KDd him.
I see it being a competitive fight for 3 rounds where GSP wastes all of his energy trying to take Bisping down and hold him down, then gas out and get KOd in the 4th or 5th.