Yes. It would. Example:
4 Atk Abomasnow Wood Hammer vs. 0 HP / 0- Def Abomasnow: 85-101 (26.4 - 31.4%) -- guaranteed 4HKO
(8.7 - 10.3% recoil damage)
4 Atk Abomasnow Wood Hammer vs. 0 HP / 0- Def Abomasnow on a critical hit: 128-151 (39.8 - 47%) -- guaranteed 3HKO (13.1 - 15.5% recoil damage)
See? The recoil damge increased when Wood Hammer land a critical hit.