Yes, phalanxes are supermen when in combat front-to-front, but pretty weak when hit to the rear properly. Best idea is to make them split up, flank them, and not hit their front unless you can hit their rear and/or flanks shortly afterwards. Throwing missiles at them from the front is waste of ammo, IMO. Perhaps historically they could take more damage from the front, but the phalanx formation in the hardcoded parts of the engine automatically raises all defense/armor stuff when in phalanx formation IIRC so it's the only way the engine allows them to be.