The Alpha Centauri feel would be really hard for this game to replicate... AC was dystopian sci-fi with a hint of Enders Game (2) (planet in book2) and things were utterly Alien. I mean, before AC no game let you build reclamation pools to turn dead people into food. AC oozed dystopian future so much that playing pro-planet felt like the right thing to do sometimes.
For Spectral empire to have the same feel, Arcen would have to make this world they put the game on truly Alien and mysterious to begin with. And the buildings in AC also had nice flavor text snippets (all voiced!) which further drove in the dystopian mood.
So yeah, would be nice to have, base building AND the AC feel...
Everything in AC contributed to it's feel, including the end turn sound... combat sounds etc. There was not a single out-of-theme element in that game.