Funny, I feel like I meandered a bit in that response.
It's one of those things I have a lot of ideas or feelings about, but I'm not always so good at getting them to coalesce into a coherent communication. I have pondered FF 4 quite a bit, in part because Namor gets a lot of flack in that issue, but haven't written anything about it. This conversation has made me realize that I've approached it from Sue's PoV and her transformation, and I need to think more of Namor's PoV and what the myth would mean to him. Is there a transformation for Hades? That's why I find your idea of Namor reconciling his internal divisions interesting.
Something I forgot, which may also explain why writers just won't let this relationship go, is that Hades and Persphone is a cyclic myth. Persephone spends 3 seasons in the world and in the sun, but she HAS to return to the underworld (the subconscious) for one season. It also explains why Sue turns to Namor when she is in the winter of her discontent. ;p
All that said, from a story PoV and for the character himself, I wish Marvel would give Namor a relationship, instead of always using him as losing part of a relationship triangle.
Well, something WOULD go on if Namor could just talk Sue into it. LOL! But I think it's cool that Namor has a relationship beyond that with Sue.