In my opinion, the best way to improve a team is with defense, and the best way to improve a defense is with a tough linebacker.
I want a fast linebacker, but I'm more interested in someone who:
a) Can shed a block.
b) Hits like a ton of bricks.
This defense needs a linebacker that can deliver a punishing hit to a running back or tight end.....someone who forces the offense to account for them on the field.
So, for me, it's a linebacker that adds toughness to a defense that frankly didn't scare anyone this season.