Make the damage latent, which means it wouldn't apply to the damage scaling that would make a weapon maximum.
Allowing a player to gain damage bonus's, but only towards specific monsters, to break the "maximum" threshold.

Reasoning:

You want to know why "Damage bonus Very High" on a Wild hunting blade is stupid? Because "High" is no different.
The bonus you get from "high" from weapons like this are completely overshadowed when you have enough damage on the other weapon's line.

A Dread Venom-latent poison with Beast Very high and a BTS (Equaling Maximum) V.S. a Wild hunting blade-latent beast high, beast very high, with BTS (Equaling Maximum, with a wasted +3 that dies in the void of damage scaling).

Dread venom is Faster, has poison, and is doing the same amount of damage to beasts. Sure, the Wild hunting blade can "Stagger more with its charge" but the charge is so high risk-meh reward it's not even worth it. Oh boy, you one shotted the turret, I did that too with my dread venom's charge. Oh, and did I mention that THE DREAD VENOM IS NOW A MORE EFFECTIVE BEAST WEAPON BECAUSE IT DOES THE SAME DAMAGE AND POISONS? I think I did, but here let me make sure.
The Dread Venom is now a more effective weapon against beasts then the other line of the same blade, specifically made for beasts.

The same could be said for the Cold Iron Vanquisher, even though at least that things charge attack seems more viable, but when it comes to damage it has the same problem. A Damage Max Levi blade hitting an undead do more damage then a Cold Iron Vanquisher hitting an Undead. Making it, damage wise, more of an undead killing machine.
This would also be applied to armor's like Deadshot Chapeau which have Med to Undead.

This way, you could do this:
Wild hunting blade: Player damage to beasts is +High
Cat cowl + BTS = Ultra Damage to everything for swords
This would make your damage be Ultra for your sword and your Beast damage High towards the player. Since these 2 don't overlap and dont become Ultra + High = Max It's more like First you apply an Ultra, then a High on top of it. Making them 2 different bonus tables, causing 2 different bonus damages to be added to your player.

This would NOT effect weapons with a UV obtained that gives damage towards an enemy, but instead would only apply to weapons (and armors) with damage UV's towards specific enemies on them.

Also, even though logic would dictate this anyway I'm going to say it in case of misconceptions, when these bonus's are on weapons they only apply to the weapon at hand. Having +High undead on your CIV wouldn't make your WHB's Undead damage higher, and vice versa.

Pet bonus's would also work this way, effecting the player's bonus and not the weapon's bonus.

Summary

Make Weapons, armors, and Pet bonus's towards "MONSTER" Damage (Gremlin, Beast, Undead, Fiend, Slime, and Construct) will apply to the player, and not towards the weapon's damage. (Such as Generalized Damage like the Cat cowl and chaos cloak, as well as Unique Variant acquired monster bonus's) causing 2 different damage bonus spectrum. That way, when you have something like the Cold Iron Vanquisher with Undead High, you can have a Black Cat Cowl and a BTS which equals Ultra and the Sword's latent Damage towards undead, which would be High. Causing them to be applied at the same time, and not being stopped at ultra. Giving weapons, like the Wild hunting blade and Irontech Destroyer, and Armors, like the Deadshot set, a more viable reason to be used.