I feel like Polarised Armour needs a buff. Either elite Combat Readiness and regular Damage Control probably do more for a ship's durability than PA.
Ignoring the elite effect since it’s not exactly related to durability since AI venting is a bit of a crapshoot, I think the value that makes PA not bad is just dependent in stacking it with high base armor, awm, heavy armor and impact mitigation all together, so that you maximize value from the skills maximum damage reduction of 0.15 to 0.10. The emp resistance is whatever it’s not especially valuable in the grand scheme of Automated Repair Unit, Impact Mitigation and Armored Weapon Mounts existing.
Is that stacking actually worth it though? Not for our vanilla ships imo, with a 6 skill limit I feel like it’s a tall ask. But some others do and I don’t have data on this so, I really don’t know.
Onslaught could go Elite IM, Elite BM. OE Elite, CE, TA, PA Doesn’t sound like a bad build, but there’s GI, MS and DC to consider.