I've found that speed is certainly not the only thing that matters. For me, this has been most evident @ HB. To this date, Ryan Houston of UNC (87 speed) has been the most dominating back I've had in any of my OD. His ability to break tackles, run over defenders, and always fall forward made him invaluable. No back has ever been able to single handedly control a game like him. Likewise, of my top 5 receivers I've ever had in any ODs, 2 of them had 88 and 87 speed. They were invaluable to me across the middle.
But to answer you question, even if the only thing that you care about is speed, recruiting is still important. If I know how to recruit well, it'll allow me to sign the power backs and possession receivers that I think will make a difference. If you know how to recruit well, it'll allow you to sign speed at every position.