When you click a builder hut's info icon, have a timer / progress bar for each builder so you can quickly & easily see when each one is next available.
This would help at higher levels where build times are often 7-10+ days and it really helps to stagger the completion times so you don't have to wait several days before you can start an upgrade. And sitting on several million in resources is inviting heavy raids.
Really. Atm you can see you five counters over buildings being upgraded. I fail to see how five additional clicks to get the same info is an advantage. :-)