I don't care that Wallace is a tick faster then Wheaton. Wallace is faster then Fitzgerald but I'd take Fitzgerald over Wallace every day of the week and twice on Sundays.
Playing WR is more then just speed. And Wheaton has is a better route runner then Wallace but a tick slower so it's a wash at best. It's more important that a WR be where the QB expects him to be......EVERY TIME! You can't put a price on that.