So making it like Fallout 1/2 where power armor made you effectively unkillable from every weapon in the game?
Terrible.
But anyways, if Bethesda does take things from NV, it will mostly be from how not to do them. We have already seen things like
-Disguise systems, and NPC reactions to armor, being far more logical, or at least far less negatively illogical, then they were in NV.
-NPC reactions to things you do, ala a reputation system, but far more personalized to the individual NPC, rather then the Borg-like single minded reactions for everyone in a faction like NV did.
-Elemental magic and crossbow bolts having various effects, and armor piercing weapons, similar to NV's alternate ammo types.
-Far greater expanding crafting systems, which let you make basically anything in the game, but is also far more organized then NV was.
In Skyrim, and Fallout 4 looks to have updated version of several of those as well.
So they obviously did look at NV, or at least all the mods NV looked at, and are taking several features but changing them to work better.