I like the Flood.
No, scratch that.
I love the Flood.
Gameplay-wise, yes, they were irritating at times. But they gave a nice change of pace from the standard fare of run 'n gun the Covie bastards, giving a nice variety to the games.
Story-wise? They are essential. Literally the entire Halo universe is built around this parasitic race. Everything that happens in the games, in the books, the comics, everything, is directly or indirectly because of the Flood.
I love the Flood. So if they're gonna be in future games, I say bring it, so long as it serves the story.
I'm ready.