it was removed for gameplay balance purposes

I didn't know it was originally gonna be in (just thought the trailer was typical window dressing)

The first asso creedo was completely busted in balance, once you got the counterattack option you could kill an entire town with no effort; I remember killing 40-50 guards at a time just doing this. All you had to do was hit the counterattack button at roughly the right time when being attacked by a melee opponent, and while blocking, and said opponent was immediately killed (melee enemies would also not attack when you were counterattacking)

Blocking completely negated melee damage regardless of direction you were facing relative to the attack, and failing the timing of counterattack (in the first one) didn't damage you iirc. I think the only melee enemies that couldn't be slaughtered by just doing this were the act bosses, so...what balance lol