I believe Holyfield was only able to compete with Valuev because the giant fights at a snail's pace and throws punches as if in slow motion. Holyfield despite diminished reflexes and speed still had all the skills to trouble the amateurish Valuev. Haye is simply too fast at this point, it wouldn't end well for Holyfield.
Haye would get a TKO over Holyfield if they were to fight right now. if you mean prime Holyfield vs the Haye of right now I see Holyfield stopping Haye....