The problem with Freeze Shock is that not only does it offer absolutely NO coverage at all (Okay, you're hitting grass, flying, and ground super effectively, but that's useless cause a neutral Dragon Claw or Outrage would probably still smash both), the charge up time means that you're wasting a turn doing nothing as opposed to dishing out heavy damage.
On a neutral target, two Dragon Claws will deal more damage than one Freeze Shock.
(80 + 40) x 2 = 240
140 + 70 = 210
You're better off running Dragon Claw or some special move like Earth Power or Ice Beam over Freeze Shock.
If you run Freeze Shock, you're still going to be walled by the same things e.g. Heatran
The only benefit of running it is that you can deal heavy damage to Ferrothorn.
252 Atk Life Orb Kyurem-B (+Atk) Freeze Shock vs 252 HP/88 Def Ferrothorn (+Def) : 76.7% - 89.77%
2 hits to KO (with Leftovers)
You're not really hitting much else.