But PGI doesn't make thermal/night vision realistic either, they're just estetical emulations at best and they even mess up with them in some maps to "balance". The only times i used them was thermal in Frozen City before they overhauled it, right now there's not any usefulness on them, they even hinder your visibility in fact.
Now, i do like the idea of thermal and night vision but only if it's done properly instead of a blurry green/gray graphic filter and not as a replacement for flashlight, but as more options for visibility. Give each of them their own advantages and disadvantages so it's up to the players to choice the right one for their needs and the situation.
Maybe they could even work as omniframe accessories, with a weight and power requirement. More customization, more options, bring it on!