You're correct in thinking no Physical BPs ignore shadows, only their elemental BPs do that. However, unless the BPs are more nerf than in comparison to the 75 fights, I can't see a RUN living through a Spinning Dive or Titan's BP if it lands, but I imagine your have enough JA's to live through Astral Flow and such.
I just haven't seen a good RUN in action TBH, no one wants them, so I don't know how well a RUN/NIN would hold hate, Idk how well they can take a Physical BP and such. I know they have Parry and Evasion, but parry and evasion don't give PDT like a shield block... what I mean by that is if your Evasion/Parry check fails and a Physical BP hits you for full damage, is it going to one shot you? Because as THF who lived off Evasion, I know full well how badly I can die horribly if my evasion check fails.
I know RUN has the ability to do -50% PDT in their TP sets with not too much trouble/sacrifice, and I know it can even go as far as -75% if you have Mythic (and if they do have Mythic, I can see this not being an issue), but sub Mythic?
Wish I knew more RUNs