I believe it was at Comicon or some other Halo 4 panel but Frank O'Conner said "The flood is interesting in Halo 4, although you won't be fighting the flood." I can't wait to see how the flood is tied in to Halo 4.
343 gives us new weapons, and the "fans" get pissed off. Don't forget people that there's old weapons in the game too, it's not just the saw. You don't have to use this weapon. Odds are you'll all love the weapon after actually playing it.