My pet peeve: when I try to click a button and just before I touch the screen it changes, so I hit completely another button (on Androod - but it is the same everywhere). So instead of cancelling a call I place another one, to a different person. No I didn't intend to call my mother in law! The solution is so simple it hurts: if a clickable area has been shown less than X ms before the touch / click, ignore the event…
Your suggestion would only work for very undeterministic parts of the UI, though.
Good UIs are predictable, and sophisticated users "know" where to click and don't need to read buttons, so they're very fast. Enforcing some delay will make the system seem "laggy".
So now you have to make a distinction between "predictable parts of the UI" and "unpredictable parts of the UI" and everything's not all that simple anymore.
A better solution is to not to pop up random things at random times in random places.