I for one absolutely hate the current system of undercutting market orders by 1 Isk with fairly priced things going unsold because multiple other items were put on the market 0.001% cheaper and requiring a lot of micromanagement.
How I would like to sell things is with a unlimited duration market order. However unlimited duration orders create the possibility of the market just becoming unmanageably saturated with unreasonably priced orders.
So in order to use unlimited duration sell orders it would come with the limitation that the price of the item will be reduced by 0.2% every day until its sold.