Considering the Attila game design of "if it moves, melee defence is 0", this destroys disables the way shock cavalry is supposed to be used - by cycle charging. Any disengagement is too lethal to be used effectively.

Therefore, the way one plays is having an opportune moment to deploy shock cavalry and leave them in melee until the target, or they themselves, are dead.

Having this in mind, I propose bumping shock cavalry base melee stats from ~0 to something below regular cavalry. This would give them additional survivability if left in melee after a charge, while leaving regular cavalry with sufficiently higher melee defence to win in prolonged melee.