I am thinking that the true strength of the TW series lies in the pre-horse and Musket eras, so I don't know how good anything like 'WW1:TW' or 'Space Marine:TW' would be. Formations, something the Total War formula is built upon, are largely rendered moot by long range repeater rifles.
My guess is a fantasy world a la 'Warhammer: Mark of Chaos' or the 'Warcraft:Total War' mod. but we shall see..
"The assumption that animals are without rights, and the illusion that our treatment of them has no moral significance, is a positively outrageous example of Western crudity and barbarity. Universal compassion is the only guarantee of morality."