How about persistent shop prices in pantheon mode?
Prices fluctuate due to supply and demand.... this would effectively balance the items since the best will be expensive and the worst (or least popular) will be cheap. Only for items though. Prices on potions should be fixed. This would also force some players to check out items they never would've touched, as well as make the core gameplay more focused on strategic combat rather than who has the better item.
What do you guys think?