Not sure if its been done or not but i'd like to see two things.
1. I want a shop. That's right, i' d like to have a shop where i could sell all those things i get on the adventures. Would be nice if the money you make by selling said items were more than selling those at a vendor , but you wont receive those money on spot but after some time. Also maybe from time to time there would be a low chance that someone else would want to sell something at that shop that i might need.
2. Rogue(or similar) class done right.