Prime golovkin would have knocked him out. Gennady was not a straight up and down boxer and was very good technically and as someone already mentioned underrated defensively. Shame it didn't happen. Beast from the east I think it was dubbed. What a shame hbo pulled out of boxing.
MW was at a weird transition at that point. Sergio had just emerged but was simultaneously headed for retirement, Pavlik was unable to get back to form after BHop, Taylor was out, Quillin hid on the sidelines, JCC was out and fallen out of favor e Mexico because of bad performance and training issues, Paul Williams went back to 154 before losing his career to MVA, and Omar Henry died of cancer. Neither GGG or Pirog got a crack at anyone other than Jacobs who...also had cancer...and also wasnt at his best. Then, as the competition faded, Pirog and GGG said fine, **** it, and were set to face each other...and Pirog had a career ending back injury...! Really, really tough breaks for Pirog and GGG.
You could be right. That's what is great about fantasy match-ups, making arguments for either side. I think Pirog based on styles would have taken it but GGG was a borderline ATG. I can't quite get there (ATG status) because of his competition, which to be fair was better than Pirog's. So I could be overrating Pirog and underrating GGG but when I watch Pirog I'm not sure I've seen anyone quite like him. I've seen others like Golovkin.