I'd love to see a better increase in the sale prices of items. It's often that I'll get multiple good weapons, but without anywhere to use them, and selling them is has such small benefit. I know there's the desire to encourage adventuring instead of buying stuff and to not game the system, but it's also pretty frustrating to have 5 good swords that should sell for at least 50 gildar and get only 10 for them each.
Any chance there could be some sort of research item or bonus to an existing one that would improve buying/selling rates when you visit the shop? Maybe on one less-utilized research item?