Hardcore Mode?
-Receive more experience/promotions.
-Not allowed to save during battlescape (Fallout Tactics).
-Fragile soldiers.
-Aggressive AI.
What about Power Armor? Are we gonna have some sort of research breakthrough which allows us to investigate power sources of sufficient energy density to sustain a full-body powered exoskeleton for more than a few hours?
Don't give me that 80's "realistic" theme when we're facing a fictional extraterrestrial life form.