No I agree that it should be a permanent ability as well, it's just that dark areas permanently look like ass with Eye of Night on all the time so the alternative plugin sidesteps that while still allowing me to use it. :dry: It's ultimately a crap reason but I don't really want to be kissing light and dark goodbye, they add too much atmosphere.
Unless those changes are piss-easy to make I'll probably hold back. It's taken me weeks to get Morrowind modded properly though so to get snagged now would be a pain in the ass!
i understand your reasons
maybe try out TLM - the lighting mod (major improvement of lighting), here's the http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=609. (i don't use the sneak plugins, don't like them; just the visual improvements)
works well with the lighting settings for the morrowind.ini suggested http://knotstheinane.blogspot.com/p/morrowind-modding-guide.html (first time i read that you actually can use linear and quadratic lighting at the same time).
edit: for easy overview, here the "code" snippet for the .ini:
[LightAttenuation]UseConstant=1ConstantValue=http://forums.bethsoft.com/index.php?/topic/1165169-btbs-game-improvements-the-topic-of-doom/0.382;UseLinear=1LinearMethod=1LinearValue=1.0LinearRadiusMult=1.0;UseQuadratic=1QuadraticMethod=2QuadraticValue=2.619QuadraticRadiusMult=1;OutQuadInLin=0
changes being piss-easy depends on your perspective
i'm not a modding genius, but minor tweaks in .esp-files via construction set are within my range (and that means in the range of anyone willing to look into it and learn some new stuff).
another suggestion from my side would be: just scale the effect strength down from 50 points to 20~25. there's a ring in the game (one you get erm... spoiler ahead... "at the end" from a certain daedra prince), that gives you permanent night eye.
it's about 20 and with TLM you can now see in dark caves, but it doesn't destroy the atmosphere.
edit2:
only weeks? ;D
look at it this way: the journey is the reward. you will always find something new to add, tweak, improve, etc.
it took me some time to realize that.