Back in the Day, I used #FVWM with focus-follows-mouse and click-to-raise only on the window decorations (not on the window itself). Displays were small, and it was very common for me to interact with windows that were partially occluded, and remained that way. I now use #AwesomeWM, and while I still use focus-follows-mouse, all clicks raise windows and there are no decorations. I just interacted with a partially-occluded window and thought about this when it raised.