Lee Evans can hurt you the most with speed and good hands, leave him alone with only a CB, a QB with time and he will score more often than not, given that not many teams have a great CBs (like the jets have with REvis) the DC will always do the smart thing, roll the coverage to the guy that will hurt you the most in the quickest fashion available (da' bomb)
Evans legs might diminish but he will always be one of the fastest guys on the field, so I don't see the team getting better without him. The only guy I can see taking his place and job, is the unproven, often injured Marcus Easley. Jones, Nelson, Roosevelt and Parrish are more underneath route runners.
BTW Kelly, the fair and balanced one, good research.