That's actually true, didnt remember all the inviolate stuff, lore and thingies like that, but gameplay wise ignoring the RP stuff for a moment, I dunno they feel like humans with internals forced on.
Dont know how to explain it cuz its probably just me but apart of the n2 tank they dont have something that makes them play different.
An example of another race (cuz I haven't played vox much) IPCs for example felt very different because you had the oil, you had the emp weakness, you have all the things with the posibrain being in the chest, being able to put your limbs back like legos, you could bring those quirks up everyshift just by reparing yourself or puking a bit of oil.
Vox on the other hand have the n2 breathing and... Not much else to show gameplay wise in my opinion, their quirks are so specific you rarely see most of them in action.
But again IPCs are a nightmare code wise so I can understand you all dont want another race being IPC 2.0 in terms of code.
The diet thing would be cool to be seen, perhaps let them eat small animals like mice, lizards and such?