It could be a lot worse, they could have made it like Skyrim Night Eye.
To be honest they should have. Not exactly like Skyrim, but RAW you dont see colors in darkness, and for most races darkvision is in shades of grey (I remember there being one race that has it in shades of red, just dont rememder wich one).
But no mater how much I want Larian to stick with RAW for combat, in this case it doesn't seem as necessary.