Then maybe Windows 9. As Microsoft knows that companies follow a 6 year life cycle, every second version of Windows, they tend to focus more to be power user and enterprise focused (much like how Windows 7 was over Vista)
Already, with pressure of power users, we might see some additional changes to Windows to reflect that in Windows 8 future updates showing the path it they are going to in Windows 9. So we have to wait and see.
For now, it's not a few GB in total that will affect anything. Each game are less then 200MB. Some are only 20-30MB. Big PC games that you buy in stores, will have no problem sharing among multiple users. Do what I mentions above with the shortcut in the folder (should be done automatically by the game setup, in most cases), for the big title games, and you are good. Just, expect for like Civilization 5, and a few indies here and there.. don't expect to be touch friendly as they are designed for the desktop PC.