The campaign doesn't teach you any keyboard functions. It's not like modern games that have tutorials or hints for everything. You wouldn't know the game has keyboard functions unless you check the options or manual. Also, I beat both Nod campaigns using only the mouse. In GDI i had to use force fire because one of the missions requires that you destroy 2 bridges.
Anyway, the online play doesn't seem fun to me. The game needs mods to make it more balanced and maybe less intense. An idea I had was the game starts at tech 1, every 3 minutes the tech goes up by 1, and each time this happens, every player get 10000. And structures have 0 build time. (the idea being that people would be willing to play at lower speed if you don't have to wait for each structure)
Also it's odd there isn't a setting to have map revealed or radar permanently on. (except during ion storms) The way I see it shroud reduces interaction between players. If you can't see them it's basically solitaire.