I could easily picture Harry losing an eye after putting on his anti-hero hat and running off on a revenge mission after Susan was killed. As Mr. Death pointed out, Odin did trade his eye for wisdom in the Poetic Edda.
Though the exact phrasing states that he "hid" his eye in Mimisbrunnr, a spring under Yggdrasil that's home to Mimir. The water there is supposed to provide wisdom, and Odin kinda leaves his eye there in exchange for a swig of the water. I've always wondered whether or not Odin's great wisdom comes, in part, from his eye still being soaked in the wise waters, and if he had some kind of constant connection to it.
Imagine Harry leaving his eye in stasis on Demonreach to maintain a thaumaturgic connection to the Island, possibly letting him access Intellectus whenever he wants. That'd be a pretty cool trade off. Though I'm not sure AlternaHarry would be Warden.