(I think we're off topic, so feel free to move these posts.)
Yes, the vanilla system works for vanilla, which has a very specific setting and a very specific concept of combat. It only works with these assumptions that your soldiers are clueless and the enemy has superior night vision. It is a very narrow and very specific design, which doesn't really allow any scenarios with a different premise.
The moment you started adding the options to modify night vision and lighting, like visibilityAtDark, these design assumptions stopped being relevant. The entire point of these OXCE additions were to go beyond Gollop's assumptions, because without revising those assumptions, you can't really go beyond the original concept. For example, you can't have human enemies who are comparable to your units; they must always be superior aliens (or equivalent). The point of these OXCE additions is to allow for other enemy templates, the original concept didn't require them at all; Gollop's mechanics was 100% sufficient.
Just to be clear, I don't think the current system is bad or that it requires any additions. I am happy with it. And I certainly don't think OXCE vision options were a mistake and should be ignored in favour of going back to exclusively shooting Cydonians.