Nobody is saying the Pats don't need a pass-rush. We all agree they need a pass-rush. The question is, how do you get those players? And history shows that the absolute worst strategy you can employ is trading multiple high picks for an unproven draft prospect. Ask Jacksonville how trading four picks to Baltimore to get up to the #8 slot to draft Derrick Harvey worked out for them. In the last ten years there have been 12 defensive ends taken in the top 10; six of them have been outright busts, and by that I mean guys who literally contributed nothing at all. We're talking about names like Harvey, Derrick Morgan, Vernon Gholston, Jamaal Anderson, and Jamaal Reynolds. If you want to go beyond the top 10, you can add Aaron Maybin, Michael Haynes, Jerome McDougle, David Pollack, Jarvis Moss, Erasmus James, Robert Ayers, Kenechi Udeze, Lawrence Jackson, Jerry Hughes and a few others. Again, these aren't just the guys who underperformed, they're guys who gave you absolutely nothing.
Nothing hurts a team more than a high draft pick who is a zero contributor, because it's a double-or triple-whammy: not only are you spending the draft ammo, you're also spending big-time money, which you then can't spend on other needs. Then, also, if you miss on a high draft pick, you still have a hole on the roster and you have to spend another pick there next year.
So it's bad enough to reach for need when we're only talking about one pick. But trading multiple high picks is taking a huge risk. If you miss, it sets your team back years, because you not only have multiple holes on your roster, you're tying up money in the busted draft pick.
The Pats' draft strategy is the best because it recognizes that luck plays a huge role in draft success. The only way to beat luck is to increase the number of chances (and, conversely, minimize the damage of failed picks). The math on the draft clearly shows that the rate of lost value as you go down in the draft is a lot lower than the corresponding increase in the bust rate. In other words, you tend to get more value with multiple lower picks as opposed to one high pick.
The counter-argument is that, sure, that works if you're looking for depth, but the Pats need impact players on defense. But if you look at the premier pass-rushers in the league, yes, a lot of them came from high picks -- guys like Julius Peppers and Dwight Freeney. But just as many were middle-round guys or undrafted guys. Look at Cameron Wake (udfa), Shaun Phillips (4th), Umeniyora and Tuck (second- and third-round, respectively), Charles Johnson (3rd round), Robert Mathis (5th) and Jared Allen (4th). Jerome Harrison and James Hall were undrafted free agents.
You're almost always better off sitting tight at your draft spot or even trading down a little, making your selection, and then praying that one of them turns out to be an effective pass-rusher. Do you want one shot at Kenechi Udeze in the first round, or three or four shots at Shaun Phillips in the fourth? The impatience to jump up and spend big resources on a celebrated pass-rush prospect comes purely from all the pre-draft hype, which is designed to make us all think that some of these guys are sure things. The reality is that nobody really knows how these guys will turn out. Not even the coaches. The Patriots to their credit seem to realize how often even they screw things up, which is why they almost never bet a lot on one player. They will move up a little to get a guy they like (i.e. Gronkowski), but for the most part they play it conservatively and shoot for depth. So if you're advocating betting the farm on Von Miller, remember that he has about a 50% chance of turning into Vernon Gholston.