After thinking about it, Eiscue seems like it's made for mind games. Its ability only works against psychical attacks, so pure physical attackers will probably switch out. You could use that turn to use Substitute instead of Hail, but if that becomes common then it becomes a coin flip. If you use Substitute and they attack, you've lost 25% of your HP. If you use Hail and they switch then you're vulnerable. If they try to remove Hail with a Dynamax weather changing attack, then you can use Hail to change it back before the turn ends, but what if they boost their stats with something like Max Airstrike while you use Hail? What if you think they'll boost their stats and use Substitute? It's like Aegislash all over again. (except probably not broken) You have to outplay the coin flip. :P
That said, Eisune feels like a gimmick. A fun gimmick that I might try out in the Battle Tower if it breaks the AI, but still a gimmick. Being able to take infinite physical attacks doesn't do much good if you have to face more special attacks, or if they just use Toxic.
Blunder Policy is a funny idea, but is only reliable if you spam something like Sheer Cold.
Heavy-Duty Boots? Hmm... *looks at Shedinja* Seems worse than a Focus Sash or Lum Berry for it, but still another way to fight KOs.