And I never said Davis can't do it either, but there's being capable, and then there's being elite. Davis is an elite route runner, no argument from me, but as far as being able to catch a ball regardless of the situation he just can't do it like williams, there's much more to it than height, tommy streeter was 6'5 and couldn't make a contested catch because he had no ball tracking, body control, or tenacity. Davis has ball tracking and body but he lacks that fierce tenacity that williams has, which is what separates the Stephen hills and tommy streeters from the mike Evans' and dez Bryants. It's a trait that's not quantifiable and not coachable, williams has it and Davis doesn't.
With williams and Davis it could very much come down to preference, do you want an elite route runner who can get open and break a few catch-and-runs? Or do you want a guy who strikes fear into the secondary because no matter how tightly covered he may be he still has a damn good chance to posterize your db and make a game changer. I'm fine either way, but I do prefer williams because I've grown to learn that flaccos lack of timing and tendency to break his targets stride means that Davis would be limited here, the YAC wouldn't come easy for him and that's a lot of his game. If flaccos passes are gonna be caught and the receiver hits the ground there, might as well get a guy who is gonna make that catch regardless of coverage.
Davis will be more reliant on precise timing and play design, williams will produce far more independent of other factors