So I read somewhere online (cant remember or find the source at the moment) that Pioli is a big fan of the 3-4 and he will want us to change to the 3-4. I think if we do that it is going to be 2-3 years before our defense is back to top form again. Right now I dont think we have any of the personnel on the DL, and really only one LB that can handle the 3-4.
I think DJ would be great in the 3-4, it would allow him to slim back down, get faster, and we can just let him get after the QB kind of like the Ravens use Suggs. I think if we just tell him kill the qb on almost every play, he will look a lot better. He has always looked good blitzing.
As far as the D-line, Dorsey isnt nearly big enough to be a NT, and I think he is too big to be a 3-4 DE. Hali is a bit small to be a 3-4 DE against the run. Tyler maybe has the size/speed to move to 3-4 DE. I am not sure if McBride will fit in either.
So if we move to the 3-4, we really only have 2 players in the front 7. That means we have to pick up 5 players between the draft and FA (in addition to fixing the O-line). I just dont see that happening this year unless we make some miraculous trade downs, trade off Gonzo and LJ for 2nd rounders (not likely), AND do a killing in FA.
If we stay in the 4-3, I think we are 2 LBs and a DE away from a good defense. It is definitely feasible to do this in one year. One LB and a DE in FA, OL in first and 3rd round, LB in 2nd round. Suddenly our defense becomes competitive next year.
I am not at all commenting on the virtues of a 3-4 vs 4-3 defense. Just commenting on the time it would take us to build a 3-4.