I said I would come back later, but I lied. I'm just gonna post piecemeal, walls of text are beyond my exhausted self right now.
To be honest, I don't really care that much about To Shatter Heaver for all magic systems, so the Rune King choice doesn't really do much besides lock in mutilation; we don't have any other magics yet that would benefit, and even once we do it doesn't really matter that much; we're a Progression Cursebearer that grows from killing things, so we'd grow faster than normal anyway. And we'd improve our magics with Picks and Arete, too, so it's not like "muh faster than normal growth" wouldn't have an outlet.
I don't really care about potential eye abilities later on either (Naruto occular asspull magic poisoned that well for me), but I do like what it does for Hunger. The reclamation of his eye is a visible (pun absolutely intended) step towards growing beyond his past; he's not forgetting it, or leaving it behind, but it would be one more way of spitting on the Tyrant's grave and becoming more of the man his companions sacrificed themselves for; a hero with a vision (haha, again!) for a brighter future and the will to strive for it against all odds.