I'm not sure why you've made that post in reply to my comments, but I'll respond.....
The Pats weren't going to spend a high pick on another Linebacker who was clearly going to only be a situational player. We had the three starters in place, Hightower to join part of the rotation as well, alongside a good-looking coverage LB in Dane Fletcher.
David's had a nice rookie year in a scheme that's pure downhill. He's excellent in coverage, as any WILL should be, but the rest of his game isn't exactly brilliant. Despite having a sturdy D-Line, he was awful when blitzing. As for the run game - well, give me no other responsibility other than shooting a gap created by Gerald McCoy, and I could look like Ray Lewis. When a Guard gets his hands on him though, it's over.
Compare him to Collins who, based on his College tape, you won't have to hide schematically and can, you know, actually rush the passer, then there's no comparison. I see Collins and Hightower as a new Bruschi/Vrabel - players who can play a couple of positions and will help continue our ability to mask our schemes and create confusion.
As for comparing David to TW, that's a false climate you're creating. You can't just say "Player A did more than Player B ergo he would have been the better pick". Nor did Wilson fill the big nickel role, seeing as we seemingly dispensed of that this year and instead went with the likes of Arrington and Cole in a more traditional role.
We needed another young Safety. The Pats looked at him, looked at every other player on their board (including David, who BB personally worked out on campus) and thought he improved the roster the best. That's the bottom line of the whole process. Projecting players to your scheme and what they will add to your organisation. The value of a Safety meant much more than another Linebacker.
As for how Wilson performed - all you need to look at is that he wasn't targeted when he was on the field. Teams weren't going after him (like they did in McCourty's first year, which people forget). That's the measure of any young player.
Moving to Harmon - only time will tell. We only know the facts - he was a core member of a defense that finished 4th in the country last year and was twice voted all-Conference. We also know that none of the amateur GM's out there had him rated higher than 5th-7th round.
But if you want to talk about accurately comparing the players we took to others we didn't then you need to do so by looking at the positions they play and the value they'd have brought. So the comparison you need to make is David v Hightower, not anyone else.