It all comes down to which of two philosphies you have. You either adapt your scheme to your current players or you decide on a scheme and then go get the players needed to run it.
I generally tend to like the first approach better since it usually gives you more flexibility and its a good way to maximize talent.

In terms of scheme or the players to play the scheme, I happen to think we already may be a lot closer to having the right personnel for a 3-4, than some of the more cynical people in this forum believe we are. I don't think this came out of nowhere, or sprang suddenly from Payton's head while he was sitting on the couch with a bag of Cheetos in week 15. I think they have been eyeballing this move for some time now, maybe a long time.

Then the bounty suspensions happened, and remember they had to construct most of the defense in the spring last year, while NOT knowing what the player suspensions were going to be or WHO would be out for how long. So that was a big monkey wrench.

Looking back in hindsight on certain newer guys we picked up on the defense, it just really gives me that feeling, that this was kinda planned out or thought through -- Junior Gallette, Martez Wilson, Akiem Hicks, Bunkley, Cam Jordan. Turns out that so many of these young guys we have been stoked about, the ones who've been getting kinda limited playing time, or being worked in to the roster, they have 3-4 potential or past experience!

But in my mind's eye, I can see this 3-4, like a lot of people in this thread also "see it" -- I'm hoping this pans out, that Payton has actually followed Parcells' advice to the letter, been patient, gotten the personnel he needs in advance of the switch, and that we have an amazing "shock the world" defense next year, that gets turnovers and finishes in the high 20s of the rankings or better.