(Not a suggestion to buff just for the sake of buffing but an observation and conclusion)
Damage Vs. monster UV's on weapons should be replaced with just plain 'damage' in order to bring them in line with CTR and ASI. Why?
Consider Vog VS. Skolver (Sword ASI VH vs. Sword Damage VH). Equal units of defence+offense, just used differently, right?
Consider Volcanic Demo Vs. Bombastic Demo (Bomb CTR VH Vs. Bomb Damage VH). Again, equal amount of defence+offense, just used differently.
From an helm and armor point of view, CTR, ASI and Damage against everything are all mutualy interchangeable.
From a UV point of view, Damage against 1 out of 6 is a bad deal with interchangeability in mind.
..or alternatively you could say in offense ability Skolver is 6 times more 'overpowered' than Vog and Bombastic is 6 times more 'overpowered' than Volcanic demo.. (but dont tell the bombers that)
-Important disclaimer!-
In my opinion a simple "damage to all" UV seems correct from the point of view of game design. It would be a function of the weapon, not it's victims, much the same way ASI and CTR are.
As for "MMO game design" I don't know. What would mean to the user-generated UV market, or the Punch crown sink, again I don't know. There would be no more 'bad' UV's, in fact there would only be 3 kinds of UV so triples would have a bit of everything. Triples would be impossible for bombs though.
And before any Lockdown T_T responses, Skolver+Striker already has has damage max. But now you have the option of basing amor choice around defense not offense (Mercurial anyone?)
I'm foreseeing damage bonus/asi vh toothpicks and gf being used on top of ice queen/merc with freeze/shock/stun max uv's.
At least with the current system, you need to use an armour than only protects from one source, or sacrifice trinket slots for vh damage.
Of course, bonus damage vs family is underwhelming in pve. Give those the ability to stack beyond max. But this suggestion also does get in the way of stopping players from facerolling clockworks. Imagine max damage from equip, added on top of a vh damage vs family.