Nigel! Go check him out on YouTube. Unlike your boy he actually threw down on his big fights and didn't try and eek a decision with a few jabs on the backfoot
A tough one this as Europe has not been over blessed at Middleweight historically imo, currently mulling over great fighters who fought and did some damage at this weight. Bob Fitzsimmons, Georges Carpentier, Randolf Turpin, Nino Benvenuti, Alan Minter, Nigel Benn and Chris Eubank instantly come to mind.
I like Conor but he'd do well to go more than 3 rounds against his dad in his prime, Pound for pound Nigel's punching power at Middleweight was up their with messer's Foreman and Tyson for my money, absolute murderous.
Might do, especially with GGG's granite chin. He wouldn't make excuses and act like a spoilt child when he loses though.