All heavy armor meant to be used with heavy swords. But it has a really bad AS( attack speed) debuff. Especially it affects troika line which already slow enough to make you dead on t3.
To fix this I suggest to add for all types of heavy armor "sword damage bonus" ( 2*-4* low, 5* med.)
That will make heavys slow, but deadly. Just as it should be.
P.S. Heavy armor = plate series.
I don't think the extra normal defense of ironmight will make it better than skolver, but could be interesting with volcanic.