For trading, it would be a UX improvement if it was possible to define a container into which buy orders are delivered.
It would also be useful to be able to sell from any container.
If the sale is cancelled, runs out of time etc and the items need to be returned to the player and the container does no longer exist or has been renamed, the items should go to the item hangar.
I believe there is a disadvantage of traders who try to only use the Eve UI against those who use automated scripts or bots.
The disadvantage is the understanding of which items are being bought and which ones are ready to be sold. Players use containers to sort and arrange the traded items. This experience is currently overly complicated from an amount-of-clicks-to-finished-market-order perspective.
Alternatively, there could be a new column in the market orders window and in the inventory that shows the max price paid for an item in a stack, so the trader can easily compare to the current market price and doesn’t even need to sort into containers.