Support Software-Side Gamma Correction
As described in https://bugs.openmw.org/issues/1983, interior cells are generally much darker than they were in Vanilla, and it becomes very difficult to see in exterior cells at night too - especially if playing during the daytime and having diffuse sunlight on the monitor. The reason for that is that Vanilla had a gamma slider you could adjust to improve game visibility on your screen, which doesn't exist in OpenMW. Since changing the actual monitor gamma would include a metric ton of hardware support, it's understandable that this is not the way to go. So why not simulate it in software? You wouldn't be changing any hardware settings but adjust colors, light intensity and whatnot in either textures or finalized frames instead.
For further reading, see this article about the principle of gamma correction: http://gamedevelopment.tutsplus.com/articles/gamma-correction-and-why-it-matters--gamedev-14466
Thanks for your time, keep up the good work. :)