As you may know, everyone is calling him OP because it has low nora cost + high hp + ghost. So how would you like it to be tweaked?
I believe that there is no way to make the Yeti Spirit a fun encounter for both parties without drastically changing how incorporeal works. I'd probably change it from an immunity from everything but magic to a strong resistance to everything but magic.
Base to 20. Like this he has max 35 hp and is killable with 3-4 magic attacks. Thats doable for every faction and every deck.
His tankability with ghost is far too excessive. 50ish HP, ghost, self amping frost aura. Just plain OP and a game changer. If an opponent gets two of these out fairly quickly you basically lost the match since they can contest fonts with little/no issue or threat of death. Toss in a mirrored shield, and wish cast on the second means he not only takes half the damage from magic, but reflects half as well.
all incorporal units are a pain in the neck to fight agains . I don't recall ever killing a spirit of the mountain.I think that all it needs is for them to be able of taking damage from other sources, or incorporal comes with magic vulnerability