My proposal for a replacement for the keyboard/mouse combo.

[Bodhesatva]

I've thought about this before, and agree an analog stick is the only thing the PC is missing for its regular setup.

However, the problem with your suggestion is buttons. In WoW, for example, I have 47 keybinds (I just counted) per character. Controllers tend to have something close to 15 buttons. That won't do for modern MMOs and RTS.