Haye has the speed and the skills to do it. His explosive force is good, but he cannot 1-KO this giant without a 3lbs-maul. Valuev has not the KO sledgehammer he should be at his size/weight. Valuev has - a passable jab - extraordinary reach - his 7' height as a default defense (difficult to touch his face) - an extraordinary chin (never been down a.f.a.I.k.) Haye needs to get in and out with speed. He must avoid a direct war - he'd loose. And he has to avoid jumping into the jab, of course. Which would be a new experience for Haye - outboxing instead of KO-punching. I bet on Haye by UD.
Won'be that tough. Haye will use the holyfield blueprint. Valuev is not even a big puncher. No problem for Haye. The Klits are an entirely different story.
If Haye puts in the kind of bodyshots he whacked Mormeck with, I can see him doing well. But if he head hunts its going to get messy.
I think you are right if (and that's a critical condition) Valuev boxes as bad as against Holyfield. I wouldn't take that as a given. If Valuev comes in the same mental and physical condition as against Liakhovich then it will be a much harder piece of work for Haye.
Holyfield did well for six rounds. He didn't land much in the second half of the fight and was pinned against the ropes twice late in the fight. Most people forget that when they remember Holy's valiant effort. Haye wouldn't survive being pinned against the ropes. He might get shocked/confused when he is confronted with Valuev's raw physical strength and weight. Haye was overexcited and sloppy against Barrett and that was the biggest guy he fought so far. He has only 23 pro fights, two fights in two years. What makes anybody think he will be mentally cool enough to excecute a perfect gameplan? He won at cruiser because of his superior athletic talent and size, despite being a sloppy fighter. he won't be able to do that against the big HW's.