I think the weight difference is actually smaller. I figure it's about 2 pounds on average, tops. It's could easily be argued that we were bigger last year. I looked at it a little differently though. While some people say that Dat looks bigger this year, so he's part of a bigger scheme, I say he could have weighed the same last year and just didn't bulk up enough. Same goes for anyone else who played in our 4 - 3 and is playing in the 3 - 4. Also, Glover is starting an NT rather than Ferg - at least at this point Ferg is going to be a role player who will spell Glover. He's not in shape and I'd be surprised to see him take 20 snaps a game. If you figure the numbers after taking out guys who played both years, and only look at who's changed the D has actually lost 24 lbs total in the front 7. Really we gained size by getting rid of Coakley and replacing him with James, something we tried to do last year anyway. We lost size by replacing Carson with Coleman. We lost size by getting rid of Wiley and replacing him with Ware. The difference is that Ware can actually play football.
I think that too much is made of this supposed size increase. Our problem last year was not size, it was an inability to rotate out DL and keep our guys fresh. We had small guys when we won Superbowls, we simply had a TON of them and guys got in and out every few plays. As a result our D stayed quick and swarming and overwhelmed our opposition as the game wore on. We tried to keep the philosopy, but our coaches and management wasn't smart enough to keep the depth to run it. As a result guys like Glover and Ellis had to play almost the entire game and wore down terribly at the end.
This year we have much more quality depth, so this year our D won't wear down. But it's not beacuse we're 'bigger' because in reality there is almost no size difference. It's because we're deeper.