I looked at winsxs of my Win8 computer. The size is 5.71 GB. It is much bigger!!! As mentioned earlier, both windows 8 and windows 7 computer have almost identical programs.
Regarding the mouse issue, I still use the original wired mouse and keyboard which came with the windows 8 computer. Since the computer is still new ( less than 2 months), I am trying to configure and learn windows 8 system. So I did not buy wireless keyboard and mouse yet.