Well for me disabling the light sensors role on display light is a very good start, and if an .ini file can be made witch can control the 5 normal steps then go for it, my 4 steps right now are 2, 50, 160, 255 (custom brightness)
2 - for night time reading and not disturbing anybody, like wife sleeping
50 - still for low light settings but easier on the eyes
160 - Normal usage (set 99% of the time)
255 - Very bright sunlight that needs to be drowned out.