I had an idea a while ago on forum.acidtu.be, So I wanted to reintroduce the idea here on unvanquished.
The basic idea is that the whole map will be encased in a darkness/fog. Humans would have to use torches or energy weapons to see and Aliens would rely upon senses other then sight. Read on for more hypothetical details.
Aliens:
-Aliens would be the mastermind behind the fog with there new introduced building (not sure what to call it yet). This building would create fog and slowly increase it while the building is alive. Of course there would be a limit to how high the levels could get.
-Aliens would only be able to see outlines if fog is heavy, but if the fog is lifted (due to human ingenuity) they would see like normally.
-Aliens therefore would have to mainly rely upon radar and the new introduced thermal vision. Thermal vision would have a limit to how long it can be used at a time and would slowly recharge.
-Lower class aliens would have a more enhanced radar then normal, and higher classes would have a less developed one.
-Higher class aliens would have a more enhanced eye and ability to see in fog, lower class aliens would have a less developed eye.
-Aliens in reach of the OverMind or an egg have the ability to see much better in the fog due to the OverMind/Egg identifying objects for them. This is for navigation in bases.
Humans:
-Humans would have to rely upon torches and lights to get around. These torches would be attached to the Human and bought in an armory. You will automatically spawn with a low tier one. Low tier torches are infinite but if you buy a better one they will provide more light, but battery will be consumed. Energy weapons or flame-throwers would produce a little additional light.
-Humans would be able to build floodlights to see in their base, and lights would also be attached to buildings to see them easily.
-Humans would have another buildable that sucks up fog.
-If fog gets to its fullest amount possible, Humans will sustain slow damage without a helmet or a battlesuit.
-As fog gets stronger, torches won't work as well.
Game play Affects:
Negative:
-If there are heaps of Humans in a team you only need one light bearer, and the rest attackers. This gives Aliens a disadvantage but then again Tremulous/Unvanquished has always been in favor of lots of Humans in one spot.
Positive:
-Teams could either invest in fogging/un-fogging or creating good defenses. This adds strategy.
-Teams would have to work together more. E.g. hunt in packs, have a light bearer and attackers, etc.
-Adds a sense of exploration to the game, that isn't evident enough for experienced players.
Of course this is just an idea. I don't expect this to be added. It would be more like creating a whole new game.