You make fun of everything that isn't Die hard science fiction so no big suprise there
No Spoon that's me, but even I can enjoy things other than hard sci-fi.
It's just that then the other stuff (mainly, gameplay) needs to be fun and immersive enough to draw my notice away from all the physical inconsistencies that my mind homes in if I'm given time to look at things at my leisure.
If I start looking for inaccuracies, I usually find them. Like, in Avatar, Pandora is well
within the Roche limit of the gas giant Polyphemus and should likely be part of the planet's rings, but then the whole moon is made of phlebotinum so I can just ignore that inconsistency (amongst others) and I can concentrate on ogling at pretty things (like blue alien girls).
Regarding the post topic: I don't agree, and on parts I have to take a stronger stance and actually have to disagree. There aren't too many aliens in FreeSpace universe, we've already seen four sentient space-faring species mentioned by name (it's implicated that the Ancients saw many, many more and subjugated them, as would be expected based on Drake's equation and the lifetime of their civilization).
On the other hand I don't think FreeSpace as a story would benefit from any more aliens. In fact, Volition's story writers did take quite a minimalist route in the depiction of aliens. It works for the story in its context, though. As space-faring civilizations, both humanity and Vasudans are utter noobs and have barely gotten away from the spawning area into the PvP territory, and their tussle attracted the attention of something a lot more experienced, stronger and uglier. It's expected that if they survive longer and expand to the galaxy, they would encounter other species that would have evolved and filled the niche left by the destruction of Ancients.
If the Shivans let them.
And what comes to different human factions, we've already seen splinter groups in both human and Vasudan camps (GTI, NTF, Hammer of Light) in the narrow scope of view given to the player through the official campaigns. The name Galactic Terran Alliance in itself implies that it is an alliance of more than one factions. Vasudans are more singular entity than humans in my opinion; in my interpretation of FreeSpace, I see humans in each system being quite autonomous and independent, with GTA and later GTVA armed forces acting on a mandate of the alliance, whereas the Vasudans are an empire headed by Emperor.