Just give the night vision the same limitations the real stuff had -- heavy weight, and limited battery life. Like, just a few turns of operation, poor reliability -- get hit, they break.
You could make us carry big heavy spare batteries around. Real militaries have to manage this additional weight, even today. Back in the 80's, you'd be carting around glorified motorcycle batteries to run your electronics.
This would give the night missions more tactical depth -- let us respond to the challenge in a meaningful way, rather than having an across the board reduction in effectiveness. Give us pros and cons to going out at night; with those pros and cons dictated by technology choices. Have "night combat" be something we could specialize in by dedicating resources to the right paths of research.
Also... what about flashlights? Turn them on, you see a few tiles further -- and the aliens see you across the map. Light discipline, anyone?