Kudos
The visibility effect and use of the perception cross attrib is very cool.
I have two suggestions;
1) - How bout a torch that increases ur night vision but also ur visibility (ability to be stealth).
and
2) - What about having creatures have different perception lvls so that you could use creatures lack of night vision (maybe Cyclops) against them almost like a night time mm perk. eg. The Chims would likely have very hi lvl of perception.