Fighting in the dark effectively takes practice. Dare I say, a lot of practice to become really good at it.
If you are not trained in low-light fighting skills, then don't attempt to fight in that environment. Remember that your adversary prefers the dark, that's why most crimes occur at night. They are comfortable operating in the dark. If you don't have the skills, then deny them the environment they prefer; turn on the lights.
I do not feel that there is any black-and-white answer to this issue. There are simply too many variables that come into play. When you look at the idea of incorporating all aspects of shooting, gun handling, and tactical movement into a low-light environment, I agree that the skill set becomes complicated pretty quickly. However, that doesn't mean that the only alternative is to turn on the lights and make the situation a fully lighted one.
One of the great things about a true tactical light is its function as a force multiplier. Bright light aimed at the other guy can selectively attack HIS night vision. If he's dark adapted, you can take that away and maintain--or even enhance--your concealment. If you just turn on the lights, you kill your dark-adapted vision at the same time and give up a possible advantage. The proximity of most light switches next to doorways also makes the activation of the switch a possible recipe for backlighting yourself, which can be just as bad as crappy constant-on "shoot me" flashlight technique.
Again, there is a big difference between clearing a house SWAT style and hunkering down and defending yourself and your family. You also must have a good reason to NOT hunker down and attempt any type of movement with a light in the first place--as Rob clearly explained on the show.
The advantage of defending YOUR home is that you can play on your terms and stack the odds in your favor. One of the things that you might consider is the idea of remotely activated lights. This can be done a number of ways. There's no rule that says an exterior motion-sensor light HAS to me mounted outside. If you put it in an entrance hallway or other likely avenue of entry, it becomes a light "alarm."
You can also purchase inexpensive remote switches that operate like a garage door opener. Hook one up to a lamp in a room removed from your bedroom and activate it from a bedside control. By strategically planning which light you activate, you can potentially scare off an intruder or at least create a light that offers you a tactical advantage.
If you have an electrician friend (or are willing to make the investment), you can even hardwire a switch in your bedroom that allows you to activate lights elswehere in your home.
Heck, even one of the "Clapper" devices could come in handy, though the audio of you clapping would obviously reveal your location.
The other thing you need to keep in mind, both from a tactical standpoint and a fire safety standpoint, is what I consider "navigation by Braille." If there is a fire, smoke will require you to stay low and will likely affect your vision. You should be able to navigate your way to other rooms and the exit by feel alone--tracking along walls and turning corners without the need to see what you're doing. Tactically, you should be able to do the same thing, knowing how many stairs there are on each staircase, where the floor squeaks, etc. That way you can navigate without having to use your light if necessary. And, as Rob pointed out, most situations are low-light, not "no-light."
The strategic use of night lights can also provide low-key illumination that can allow you to collect family members and hunker down without having to--or at least before you may choose to--"pop a flare" by flicking a switch.
Again, I don't feel there is an absolute answer to this--except to train actively, develop good skills, and realistically apply those skills to your specific personal defense needs.
Stay safe,
Mike