I think you make a fine point, Ken, and I respect your stance on the matter. I can't however, agree with the thought that we didn't select anyone due to Tyms (barely re-signed after no one else showed interest), Boyce (cut, and re-signed to the practice squad), and Dobson.
In other words, you may have a much better argument pointing out the low numbers for the WR3-4-5 positions, historically; or the thought that there's enough competition with Gibson (don't sleep on him), Dobson, and Dorsey. Let's remember that Belichick just made bigger name FA Stevie Johnson an offer, so obviously he's not quite as "satisfied" with the depth chart and potential as some here are suggesting.
There may/may not be a relationship between prioritizing other positions and choices over WR in the draft, and Belichick being happy with guys like Aaron Dobson, but I don't think we can make the strong assumptions that Belichick feels comfortable about the position. Just my opinion, of course.