The reason military sci-fi is basically retreads of WW2 with sci-fi dressing is because military sci-fi fans have huge boners for WW2 and will never get sick of re-reading the battle of the bulge but with robots.
Well I like World War 2 and now I have a boner so I guess I can't argue.
Anyway I've tried war several times in my games. My original D&D game, the first thing I ran, spent it's last quarter detailing a war between the PC's country and the evil nation nearby ruled by an evil dragon. That was pretty vague since it was a first time game and everyone was in high school.
Lately I've found myself flirting with war often. My Epic D&D game recently was entirely about war. My PCs where not interested in the specifics of the war, though I offered them the positions of generals and tacticaians in the setting. They only wanted to kill dudes of their own level so they got turned into a NAVY Seals style unit.
CthulhuTech is all about war, several different ones occuring at the same time infact. Tried to push that but about half my players didn't want to deal with what they considered a depressing setting (it's based on the Cthulhu Mythos so humanity is losing the war). So we played a Tager game that was more akin to supernatural superheroes.
So, yes, I want to do war but my players won't let me.
*sigh*