Well, I'll be sad not to see further Mance developments, but I agree that we probably won't. I'm just really confused about where Sansa's story could be headed. Isn't a big stumbling block to any new marriages her current marriage to Tyrion?
I am not sure if anyone else has mentioned this, but I believe the mythical twins Ser Arryk and Ser Erryk who die on each others swords are a clear reference to the Arthurian legend of Sir Balin and Sir Balan. These twins who are mentioned in Malory's Morte D'Arthur and Tennyson's Idylls of the King are tragic brothers who, despite their nobility, end up killing each other. A small reference but worth mentioning.