I was actually just about to make a thread about this topic. I will post my suggestion here.
In addition to the better event handling that everyone above mentioned, I would also like to suggest that destroying improvements not be so simple as walking over them. It's cheesy (in the sense that it's abusable against the AI to camp their improvements and bankrupt them) and frustrating when defending against many waves of attackers, they ALL walk over your clay pit on their way to your base, because, why not?
Please make it an action that consumes a turn or two, thus giving the defender time to interrupt the destruction, and saving us several dozen re-queing of clay pit construction, simply because it's located in a high traffic location.
