Your key rule is my attitude to everything in existance - I use it to justify war as a nessecity in the evolution of civilized nations and the avoidance of stagnation (that and Gundam Wing references).
I use it to justify -not- mixing Muller corners with their corners until ive only some of it left.
I use it to justify Meshuggah as ruling.
Of course, were it all relative, there would be no possiblility of their existing correct morals; Well, there doesn't, but theres a range within which it all works.. An extent.
Sometimes providing too much contrast all the time fucks !@#$% up with a generic, obvious and homogeneous tone that sucks only from the weak.
But the rule still holds, for it is applied to everything, and that means itself; Even levels contrast themselves, need to be contrast.
This is why Killswitch engage suck.
There also has to be a slower wave of overall contrast between levels, independant of the instantaneous events that create the tighter contrasts mentioned in the article - You need soft calm villages, relaxing scenes, reflection, fast paces riots, scary goins on O_O.
eg, take dungeons being dungeons, and the overworld NOT being dungeons.
The divide is very relaxing and an integral part pf zelda games.
Global contrast => global expectation. The article mentions expectation of course, and likewise to little events,. there are alot of obvious expectations - Evil powerfull end bosses, harder dungeons, misery right before the light at the end. Expectations to be fullfilled, twisted, turned, made to look like their not going to happen and then only to fall out of the sky.
This article is something valuable, good reading material for inspiring or directing aspiring designers towards the right ideas.
It wasn't really specific to 3d level design.. The same rules can be applied to any 2d scene, and even the same examples (falling down holes, seeking for bomb walls, freezerz jumping out of walls in the first, silent, calm, still light-coming-in-it-peacfull entrance room of the ice dungeon; Even my sentence there, with the '-'s inbetween the words to throw those words together and emphasise my point dramatically.
This, is a lesson for LIFE.
Apply the wise possums words to your cloths, your food, your music.
