absolutely not. one of the things I love about AoS is the wounds carry over. in 40k it makes sense. one bullet isn't passing through two space marines in power armor. but an 8 foot bolt from a ballista on a Stegadon could absolutely pass through more than one guy in medieval armor as it crashes into the formation.
str/tough I could get behind, as from what I'm told ( I also didn't play fantasy) it was a mechanic that existed in this game prior.
The issue with wounds carrying over is that you're rewarding overkill which ends up meaning that any weapon (or mechanic) specificly designed for taking down big scary stuff is Always going to be just as effective against cannonfodder as well (unless you make up some really convoluted rules)
For example, let's take our carnosaur's bite attack when buffed with a starpriests venom, an attack designed to deal with other big monsters, we even can get a bonus on our rolls towards actually landing the attack on monsters. It now deals 6 damage. Based on its size it can fit roughly 1 skaven in it's mouth at a time, maybe 2 if they cooperate. What's causing the other 4-5 skaven to die in this situation? Seeing their "friend" eaten gives them spontanous heart attacks? And that's just one attack. A Lucky carnosaur with a starpriests venom can somehow eat 30! skaven but only hit 4 of em with his claws in one round of combat. He can wipe out entire horde units with ease, but has bonusses indicating he's supposed to be a monster hunting unit. That's kinda weird.
If you want to represent something like a balista potentially hitting multiple targets cause it can ricochet or just flat out passes through weakly armoured fodder, give it a higher volume of attacks.
In that way you can get the following ways of making dedicated weapons:
High volume of attacks + low strength + low damage = anti horde weapon, ineffective against powerfull single entity units
Low volume of attacks + high strength + high damage = anti single entity weapon, ineffective against hordes
It could be as simple as take whatever the wording is in 40k about how to allocate wounds, and then make an execption for the monster keyword
It's probably going to be a disaster to balance if exceptions become common. Too prone for abuse. 40K again has a very good solution though, different modes of attack or ammo used. For example an armiger warglaive (a sort of mini-40K-knight, it's about the size of a carnosaur modelwise) can either make a normal attack or a sweeping attack with its chainsword. The sweeping mode has twice as many attacks but only hits at half the strength and does less damage per attack.