Not going to happen.
One, we don't do hand-holding. But the more important reason is that there are many things in the game with a random factor, and that is often calculated when you do an action, e.g. build a recruitment center. If we had an "undo" button, people would just try-undo-try-undo until they get what they wanted.
And if we allow "undo" only for a subset of actions, that would be confusing.
