OK, armor in general really needs an overhaul, but the Shadow Lair sets are a good place to start. They're the hardest armors in the game to get outside the 5-star Black Kat and other Kat Raiments, but between them, only two aren't useless and are worth the time to get: Mercurial Demo and Snarbolax.

Ice Queen is mediocre, just like every defensive armor set, and Skolver has almost all of its benefits, except it doesn't blow.

Heavenly Iron is completely outdone by Skolver and Snarbolax, which is stupid, because both are easier to get. The Shock penalty only makes it even more worthless, and Curse protection is almost never worth using. The only place this armor could be useful: Shadow Firestorm Citadel, and you still need to mix it with a piece of Fire armor.

Arcane Salamander's monster family boosts are lame, and can be achieved easily with UVs.

Finally, Almirian Crusader is even worse and gets totally outdone by Heavenly Iron. Again, Curse resist is impractical, and the Fire penalty makes it suck in the one place it could have some value besides Legion of Almire, SFSC.

This is how I'd change these armors.

Ice Queen

+Universal "Low" CTR.
-Minor Fire penalty.

We're lacking armors that give CTR. It lines up with Ice Queen because her spinning attack can be considered "charging."

Heavenly Iron

+Replace Shock penalty with Shock RESIST, equal to Snarbolax's resistances. Keep Curse resist the way it is.
+Replace both the Fiend and Sword damage bonus with Medium sword ASI.

I can't think of why they'd give this such a nasty Shock penalty. We already have two Sword armors that give damage bonus, and only one ASI, so this works. Now, it's an even better set for SFSC, as long as you mix in some Fire gear.

Arcane Salamander

+Swap out the Slime and Beast buffs for MSI "Medium," keep everything else the way it is.

MSI is already rare. This could be a viable armor for Bombers who have CTR variants and trinkets. If Medium is too much on both pieces, then it doesn't have to be symmetrical; the helmet could give Low MSI, and the suit gives Medium. Reptiles in real life tend to move fast; makes sense. (Honestly, the reason I swapped in MSI is because I couldn't think of anything else to make it viable for all weapon classes.)

Almirian Crusader

+Swap Fire penalty and Curse resist for Fire and Curse, equal to Snarbolax's defenses.
+Universal "Low" CTR.
-Minor Shock penalty.

Not much else to say here.

By the way, when I say things like "Medium" and "Low," those are tentative amounts, and would probably have to be tested a lot to balance out.