Evander Holyfield, Muhammad Ali, McCall, Chuvalo, Vitali, all spring to mind as possible examples of guys who would have taken that shot. Some guys like Holmes might have been knocked down or hurt badly by it, but that alone wouldn't put them out.
Only Chuvalo and perhaps McCall would be caught in the same position when they got hit. The others would be moving away. Walking into a shot like that while throwing exponentially increases its power.
True. He was totally squared up when he got hit. No give in the legs to help absorb the shot. Nowhere for the body to roll to. Just 220 lbs of fist smashing straight into the chin. Hard to see anyone taking that under those conditions.
Barrett has that wide stance to generate all the leverage for shots. Its a component of those haymakers he wings. Cameron did well to advance into him while throwing.
Barrett staggered Nikolai Valuev with an overhand right in the first round, made his knees buckle a bit. Though he got a bit dominated by the end.
Barrett throws with everything. Haymaker covers it. It's fairly bad form, and he isn't quick, but his punches usually carry everything he had with them.