I mean, the cutscenes for wonders in smac really enhanced the immersion of the game. Galciv could do loads of them too.
First contact
First ship
First capital ship (done)
Key technologies - small medium large huge carriers
Doomsday weapons (reaching nightmare torpedoes etc)
So many more!
I mentioned this once earlier but even the tech text etc could really use an overhaul. Check out smac again for inspiration! Content writers ain't expensive