The actual choise for the show desktop grid / show window modes isn't ideal. From my point of view keyboard shortcuts have to meet two requirements. They have to be easy to memorize and they have to be easy reachable on the keyboard. While I think the first point is no problem the reachablility is not optimal wiht the current Ctrl + F8 [F9][F10]. Regarding in terms of physical space Ctrl and (e.g) F10 are far apart from each other (Ctrl. in the extreme down/left corner and F10 in the extreme upper/right corner). To press both keys you have to leave the 10 finger baseline on the keyboard (OK with the left hand not as much as with the right hand). After pressing the shortcut it's not that simple to reach the the 10 finger keyboard baseline as it ideally could be. Since the the show desktop grid / show window modes are elemtary features to organize the desktop or to select windows quickly they are often used (I think so) and should be have shortcuts which are better reachable.
Suggestions: - use only one key - e.g. F10 - so only one hand have to leave the keyboard baseline (to get back to the baseline the right hand can orientate on the position of the left hand). This possibility means checking if there is no conflict with other applications.
- chose two keys where you don't have to leave the baseline with both hands and which are not that much far apart from each other.