The defense is likely going to play assigned gaps instead of "two gapping".
To play two gaps, you need oversized, strong men that can routinely disengage from blocks at the point of attack and quickly close within a short area. Seattle is conversely loaded up on lighter, quicker guys (Mario Edwards, Dre'Mont Jones). The kind of guys that have to hit gaps quickly. They can still shuck blocks, but they are doing it on the move, on their way to a predefined spot. Dudes that live in the backfield by design. It is a different animal then statically absorbing the charge of an offensive lineman at the line of scrimmage while attempting to diagnose a play. Like I said, you need huge, strong men to routinely do that.
Another aspect is that with the combination of Brooks and Wagner, you are getting two tackling machines (if both are healthy and, on their game). Further, Wagner can probably take the deep middle better in the cover two than Brooks can just because of recognition and experience. Hence, I believe the team will play cover two more often than last season which theoretically puts the linebackers in better position to stop the run game as well. Further, the team strength at corner allows the team to put more of an isolated load on their corners and resultantly frees up the linebackers and safeties for more exotic, disguised blitz packages and coverages. A means to put Jamaal Adams to purposeful use.
In summary, I expect that a few tweaks with the lighter, quicker defensive front will allow the defense to handle the opposing run game more effectively than last year because of the strengths of Bobby Wagner, Jordyn Brooks and the cornerbacks taking on more responsibility in coverage (freeing up other positions). I bet they stop the run much better than last season.