Due to Halo Reach's setting there will no longer be any battles against the Flood. This is a shame as the Flood offer a nice twist to Halo's gamplay by throwing enemies in your face rather than having them sit back and shoot at distance. My idea is that Bungie should make it so that certain waves of Firefight actually contain Flood enemies rather than Covenant. Or maybe even Flood Firefight levels with no Covenant. This would work fine as Firefight is seperate from campaign. I also think the Flood are more suited to Firefight scenarios. Having an enemy hunting you down and trying to surround you is more of a Flood trait than a Covenant in my opinion. Maybe this could be released as DLC, I dont think it will be in the shipped game but we can all hope