I've noticed definite differences in armor, at least as far as damage goes, in a number of fights. The poise mechanic is still blorp, but there have definitely been times that swapping out my armor affected my longevity in a fight in regards to taking damage. Hell, the final boss almost entirely depended on me having higher absorption.
Also for the N
K
fight, as many have said before (including me!) in the first phase never stand underneath him. Stand in front of him and lock onto his head. He will NEVER use the AOE flame attack which is his only problematic move. For the second phase, your mileage may vary, but if you have difficulty dodging all the lightning then do what I did and use a shield with High Lightning Resist. It'll stamina bounce you but I never once didn't recover before I could dodge his follow-up. I couldn't dodge his lightning summon or lightning pulse so I just blocked it and took a chip of damage then soldiered on. I...don't see him being a damage sponge. He took a comparable amount of damage compared to most other bosses. It was only a long fight due to needing to only hit once or maybe twice before going on the defense again. At the end he had...15% of his life left when charging for his AoE and I just ran in and flurried him with maybe 4 attacks to kill him before it could go off.