Depends on matchup imo.
If HB is blocking you on the weak side, maybe speed>strength>agility
If FB is blocking you, and is good at it, agility>strength>speed
If LOT is blocking you, agility>strength>speed + probably kiss your ass goodbye.
Try to play the right side if you want to blitz or having an intensely strong, pulling D-line.
If a TE is blocking you, strength>agility>speed. Depends on his build.
Can't evidence any of this aside from speculation on typical builds.