You say that, but TF2 is all about immediate team (and class) recognition. If you can't tell what team someone is within a nanosecond of seeing them, that area of the map will need brightening up. And who's to say that the eye-glowing isn't someone's killstreak kit?Keep in mind MVM maps don't suffer too much by being dark because you're fighting glowing giant robots and not team-colored clones. There are also only 6 of you and tons of them, so team recognition is usually not an issue at all.