Nowadays, zombies aren't mindless, Syphonz. They're usually Infected humans suffereing from some rabies-like virus (which actually, sounds quite realistic, and I think there are fears among some experts that similar things could happen in real life, although not on the level of a zombie game style apocalypse...). However, controlling them does make sense provided there is some scientific framework to base the control system in. As for an RTS, apparently the Flood are going to be a non-playable army in Halo Wars. Fine, again they are unplayable (and yes, Microsoft have assured us they're going to be following canon very strictly, given the humans don't know about the Flood until the original game...), but at least they are present. This could be a stepping stone, perhaps, to a true zombie (sorry, Infected) RTS in the near future.