@Solarius: Have you thought about something like what got buried in the hangar discussion?
I think the one thing that looks increasingly appealing to me is to make the opposition actually coordinate their missions so just hopping from one to the other with the Kitsune and occasionally swatting a UFO won't work. Something like the UFO swarms/waves adopted by several (most?) more modern X-Com-likes.
I don't think there currently exist very good tools to make something like that happen in OXCE, at least not without seriously restructuring the mission scripts. And the mod has moved away from a mono-focus on just one enemy ever since the beginning.
But I just can't but remember how much more
fun the geoscape part with this kind of dynamic was in Xeno1/UFO:ET. Neither the original X-Com nor any mod I've played (except Piratez to a degree) has quite scrathed that itch.
Also, I wanted to say my piece about the EMP discussion going on in the bug thread. I think the simplest solution would be to let the jarhead mission have a separate clue that guarantees 100% mission spawn that comes from one of the more obscure but readily available investigations. Perhaps the 'secret files' item? Or the 'really secret files'? Probably not the 'really, really secret files'...
Although maybe some promotions could come with an "X-Com files" item that tells us about our predecessors?
Because it's true that gating a whole fun weapon class behind a 7% chance to appear is kinda excessive. Then again, the mod has a lot of this kind of gating.