How can I deny "android:keepScreenOn" to a misbehaving app? There is a misbehaving app (com.funplus.familyfarm) that keeps the screen on even long after it is ever needed (the app re-synchs with server and reloads the interface after some idle period). 


  The app is not running in background. It is the active app currently shown on-screen.


It makes my device almost too hot to touch, not to mention the battery drain.

Is there any way for me to deny the "android:keepScreenOn" to the app, or to do something (like a Tasker task) to kill it after an idle period?

I am running ICS 4.0.4 and the device is rooted. I have purchased Tasker Pro, but really do not know much how to mess around.
Xposed Module

Since your device is rooted, you could install the Xposed framework and then install a module such as App Settings. It lets you tweak settings for an app. In your case, it lets you tweak whether to keep the screen on or not (according to its page, at least).

The Xposed framework has tons of other modules for tweaking the inner workings of Android.