These are just some small enhancements to improve quality of life. Nothing that changes or adds mechanics, just simple UI changes.
1. On the crafting window that opens when you long click and item to craft, or click an item for which you don't have the materials: If you have already collected, in addition to the button to pay gems for more materials, also add a boost button that will automatically spend whatever the current minimum amount is to boost the corresponding building. This saves a trip out to the City screen and then back to crafting.
2. On the same note, if you are in the crafting window and have already collected and still don't have enough materials, include an upgrade button. This will automatically start an upgrade of the lowest level resource container for that item. This button will only be visible if you have no other upgrades going on and can actually start a new one.
3. When suggesting an item to a hero to buy, the list of items is pretty much unsorted. It would be nice to have the options to sort this list by the amount of energy needed to select the item, by quantity of item, or by level of item. It would also be nice if the item level was displayed on the cards in the list.
4. In the Trade House, it would be nice to have a filter that allowed us to filter by offers and requests for gems, gold, or both.