Don't try to change the arguement, you posted earlier that you need 3 big DL to stop the run. That is compltely wrong and I suspect you know it. Most 4-3 teams over the years have use to small DEs.
I don't know what system the Patriots are going to use this year maybe they go back to the 3-4 ? Maybe Belichick is working through different options.
But here is what we know the defense was horrible last year so BB may want to do something very different.
Wilfork is the lightest he 's ever been.
I first guy in FA we sign is a penetrating DT.
In the 1st 2 practices we lined up with samll DEs exclusively with Deadrick going to DT.
So the idea that our base DEs could Nink and Scott or Bequette and Jones is a real possibility.
You are correct that we don't know what BB will do. Because of the confusion around the terms "base" and "sub", I prefer to think in terms of 6 and 7 man "fronts" (DL + LB). A couple of thoughts:
1. BB has openly noted that the league is becoming more spread out, and that there is a trend towards slightly smaller, quicker players. It's not clear if this means using more 6 man fronts, using smaller/quicker guys in 7 man fronts, or both. The percentage of 6 vs. 7 man fronts - and even 5 man fronts - will probably vary from week to week depending on the style of the opposing team, and will also depend on the health and availability of key personnel.
2. BB has always valued the ability to stop the run, and it has generally been a hallmark of his defenses. It's hard to envision him selling out on that to become more pass-oriented, regardless of what scheme he runs. So I think that whatever defense he puts out on the field in 1st and 2nd down situations has to be at least competent at defending against the run. While that doesn't require 3 300#+ guys, it does require guys who are long and strong enough to set the edge and 2-gap. It remains to be seen how well 270-280# guys like Jones (with a few lbs. added on) and Bequette can fare in that role, compared with bigger guys like Deaderick and Fanene.
3. You note that "Most 4-3 teams over the years have use to small DEs". But teams around the league that run a 4 man line in a 7 man front vary tremendously regarding the kind of ends that they look for. Sure, Indy has used 250-260# guys at both ends to maximize pass rushing and speed, but they are one extreme generally have been weak against the run. The more complete 4-3 defenses generally have more heft at at least one end spot. San Francisco - the best run defense in the NFL in 2011 - has 285# Justin Smith at LDE, and the Jets had 285# Shaun Ellis at LDE when they ran a 4-3 (and they are considering using 315# Muhammad Wilkerson at LDE in a 4-3 this year, with 280# Quinton Coples at RDE ). Seattle uses 320# Red Bryant at one end, with 260# Chris Clemons in the Leo role at the other. Baltimore has used 340# Haloti Ngata along with 260# Terrell Suggs at times. The Giants have had 275# guys in Justin Tuck and Jason-Pierre Paul, but both have exceptional length and strength (perhaps Bequette and Jones could evolve into something along those lines, but it's a lot to expect out of them as rookies), and New Orleans has something along those lines in 287# Cameron Jordan and 282# Will Smith. There's no one model that works, and a lot depends on individual defensive philosophy and approach, and especially on the players involved.
4. BB has played both 4-3 and 3-4 schemes with a 7 man front in the past, and has used a hybrid approach integrating elements of both, including last year. That generally requires that at least one end be capable of playing a 2-gap 3-4 DE role. Ideally both ends should be capable of playing 3-4 or 4-3 DE, setting the edge, 2-gapping, being pass rushers, and even dropping into coverage on occasion, but those guys are very difficult to find. There are guys who fit that mold - JJ Watt and Shaun Ellis (in his prime) come to mind, and there are some intriguing guys for the future (Margus Hunt, for example). Finding 2 of those guys is very difficult, and getting 1 would be a coup. In the past, there has been a tendency to make tradeoffs, with the RDE being more of a lighter rush-oriented player (Andre Carter, Mark Anderson) and the LDE being more of a heftier, run-stopping 2-gap player (Brandon Deaderick, probably Jonathan Fanene).
5. I wouldn't make too much out of what BB is doing in the first 2 practices, or even out of what we see in training camp. BB tends to be evolutionary in his approach, and he generally focuses on getting a "vanilla" defense down before getting more fancy. He often doesn't like to show too much to the rest of the league too early, and often plays fairly vanilla D in pre-season games and even at the beginning of the season. And he tends to be personnel driven rather than driven by adherence to a given scheme or ideology. I think that he is likely "working through different options", as you suggest, and expect to see him do a lot more of it. Even if the eventual goal is - as I have suggested, as much as anyone - a fluid defense that can morph between schemes without changing personnel, it's unlikely that we'll see it burst out in full glory right away. It will probably be much more subtle, and more clearly related to traditional schemes that BB has run in the past, at least at first. My guess is that he has studied some of the more successful defenses around the NFL, and that he will be incorporating stuff used by teams like the Giants, San Francisco, Baltimore and Seattle.
6. With those thoughts in mind, I think that it's unlikely to see a guy like Rob Ninkovich at LDE on 1st and 2nd down situations, at least most of the time, though anything is possible. I think it's much more likely that we'll see someone like Jonathan Fanene or Brandon Deaderick at LDE and then moving inside on 3rd down (think of how Chris Canty is sometimes used for the Giants), with a guy like Jones/Bequette coming in as a sub rusher or a guy like Hightower/Ninkovich moving up on the line in more pass oriented situations (in a Mathias Kiwanuka kind of role, to once again draw a comparison to the Giants), which is pretty much what Andy has suggested. But I have no crystal ball as to what BB intends.