For me, the real benefit of Von Miller aside from his stellar play is that, from what I can tell, he provided the vision and the push for AD to, unbelievably, become a better player.
Now Youngblood53 posted some interesting stats showing the defense hadn't gotten that much better but to my eyes, there were somehow better in terms of maybe being more "clutch".
The way they shut down the 49ers run game, the way they shut down the bengals after those 2 quick scores, both of which were horseshit type scenarios against the defense was amazing. The way they ended the 49ers and Bengals game was amazing.
I'd err on the side of paying to much to keep that fairy dust swirling for a year or 2 more.
I'd go bargain shopping where we traditionally have - at Guard and ILB/RB.