Guilli:1-Two campaigns (anyone remembers halo 2?) But covenant campaign should NOT be the same missions only from the other perspective. (you get the idea)
Edit - Quote of Eternal Vigil:
I would of liked a Covenant Campiagn, but I aslo remember the backlash to Halo 2 because of the lack of the Chief.
I don't think there would be much backlash on HW as you don't really get very attatched to any specific character in RTS like you do playing as the same one constantly, thats my thoughts anyway.
I have a fire proof suit, don't try it.