There's no doubt the outside linebackers benefit from the defensive line getting a push inside on passing plays but that doesn't make the DL more important than the edge rushers.
BTW the Packers don't use four down linemen in their subpackages, mostly lining up with only two.
Funny, I was well aware of this 4-4-3 formation that he's been using for quite some time....if you don't believe me, I even googled it for you for your own reading:
http://allgbp.com/2013/07/02/packers-playbook-part-8-the-hippo-defense/
You're welcome.
How exactly do a couple of DTs going up the middle of the line help the OLB win his battle with the opposing tackle? They could give less of a crap about a slow 300 pound DL who isn't even in their area when they have athletic pass rushers on the edge to keep away from the QB.
I'm assuming you've never played LB in a 3-4 Defense, so let me explain:
Obviously in a 3-4 defense the "3" comes from 3 down linemen. Obviously on the offensive side, that's 3 DLs going against 5 OLs, plus the possibility of a TE or a RB in the backfield. Depending on how the pass protection is designed, a OG can be shifted to double team a DE or the NT/DT based on the flow of the play. Since a OLs first step on a pass is backwards, they are somewhat presented with a "choice" on which DL to engage. That's why you often see the C pointing at the opposing DL right before the snap, he's literally calling the pass protection based on what they see the defense lined up in as far as gap assignment and what they've seen in film, normally it's a series of dummy calls to get the DL to push right into the advantage of the OL.
So with that being said, after the snap of the ball if the OG is engaged with the DE, which is highly probable, given that the offense knows there are 4 LBs capable of bringing the blitz, the OT is one on one with a 3-4 OLB. It's up to the OLB (In this case Elliott) to win that battle, or at the very least, demand the additional attention of the RB in the backfield to allow another LB in the scheme to make the sack.
This all goes back to the DL, SOMEONE has to demand a double team. If the DE(In this case Daniels) demands the attention of the OG and the OT on his side then that leaves the OLB one on one with the RB in pass protection or he has a clear path to the QB. If the OL is winning the battle with the DL in a 3-4, then the OLBs are going to be tangled up with what is commonly called the "trash" of the LoS, because there'e not enough push from the DL to where the OLB gets a free rush. At the end of the day the OT and the OG or if it's the weak side the TE in a block and release route as well only need to "chip" or hold the OLB for about 1-2 seconds to allow the QB to make a 3 step drop and throw the ball. In a shotgun formation the QB is already gifted an additional 1-2 seconds by being futher from the LoS so that chip turns his 3 second read into a 5 second and possibly longer read and throw, which is when the play breaks down and WRs typically find a way to get open against the secondary(Randall and Rollins).
Fortunately, the silver lining to this is the fact that with the OLBs in a 3-4 caught up in the trash on the edge, someone is still available to sack the QB, and that's the ILBs(In this case Perry). As the play develops if at least one of the ILBs are still available despite the pass coverage he has a choice of which gap to shoot, whether it's A or B. Unless the ILB has a predetermined gap that must hit based on design he can run right through the line if the NT who's hopefully found some way to demand a double team of the C and OG; or if he's one on one with one or the other, he can flow right behind the initial push, which leaves either just a RB to beat or a clear shot at the QB. At the very LEAST, once the QB sees the ILB coming he'll either take the sack, force a throw, or scramble.
I could go on and on about various defensive scenarios in a 3-4 involving run fits, blitz packages, and executing coverage, but I think you all should get it by now. If you don't win the LoS, things can get quite difficult, even for an edge rusher.