They want to show the JSDF in action, but need to get around real-world considerations, many of which shall not be discussed here. Easiest way to do that seems to be pitting them against a foe not of this world.
Which I'm fine with, or even something like Rescue Wings (Yomigaeru Sora, good stuff) mixed with Tokyo 8.0 - though, I suppose post-Touhoku, that's not coming back on TV for a long damn time. I'd be fine with space aliens, or anything else, or even just on-post shenanigans between bored soldiers. Or something like Airbats, extended out. Plenty of options that sidestep Rule 4 plenty.
Now, sticking my face into Rule 4 territory and blowing bubbles in it like bobbing for apples, Zipang's a fantastic story but good grief it's political as hell. So that's all I'll say about that.