On the 'This building has expired' screen, why not put a 'sell building ' button, there is plenty of room, and is the logical next step.
This part is a decent idea, but as
@defiantoneks says it's doubtful it will be accepted by the devs. That doesn't mean it shouldn't be presented, just my opinion that it won't get passed on, much less implemented.
As it is now when you click on the building, and it brings up this dialog.
You wish to have a button (like in the pic below) added that lets you sell the building right now instead of having close this dialog, put the city in Sell mode and then finding the building again to sell it. The situation is exacerbated with the current sell dialog since it doesn't show the building is expired. Maybe I clicked the building next to it that hasn't expired, and I 'accidentally' sell it. In the browser buildings can 'hide' behind others and you'd sell the wrong one. But that's a different problem and not truly germane to this thread.
Dialog for the building when in sell mode:
You could also have a check-box when you click on the building 'Sell when expired'.
This part I disagree with. If I understand it, when the building is placed but not expired, you wish to have a checkbox on it so the system will automatically sell it when it expires. This kind of sounds nice as long as it applies only to that building and not also to others. However, it just doesn't quite feel right to me. Who, knows. That feeling might change. I just have to not click it. The above building is a 1x1.
As an aside, I keep expired 5d fighting building since they give a goodly amount of coins and hammers when sold. I sell them when I've fed the brown bears, so I'd never want them to auto-sell. But if I did, what happens when they would overflow the cap in the MH? Maybe the first won't overflow it, but the others would. Does the system have to keep checking to see when it can be sold? Does it just sell them? Does it bring up an ad you don't want?
This even applies to culture from the buildings. Would it keep selling the buildings even if it would lower your culture below the required culture? Remember, the program has to be coded to handle the off-normal cases.
PS: I'm obviously talking from the browser version since it doesn't have the Hide Buildings the App version has.