Most UDFA prove why they did not have a draftable grade, we are not the mecca of UDFA players even if one sticks they're shortcomings typically show and you see why they weren't drafted.
Very true that we need to hit on our higher draft picks. There is no replacing that.
But to tune the bottom of the roster (or find the occasion diamond in the rough like Pierre Thomas or Lance Moore) I think it's worth grabbing a ton of these guys to see how they develop for longer than mini camp and fringe roles in training camp. We have an entire bottom of the roster we can turn over without much loss in talent. The ones that have been here as career special teamers and practice squad players aren't worth caring over because we've seen what they are and they aren't contributors. So why not flush that whole group and grab a whole new group to see if any grow into anything. Really spend some time coaching these guys and give them a real chance to catch on. If we can find a RB2, TE2 or WR3 on a UDFA contract we'd be setting ourselves up for the next few years. It'll be up to the coaches to do those evaluations and maybe pick up some other players after roster cut downs.