While cross wrist grips with flashlight and pistol may look just fine in the moves, it's not something that we civilians get to practice in live fire exercises...and without that training, I'd venture to say, it'd be nearly impossible to accomplish in a night time defensive encounter.
I'd disagree, pretty strongly even. Night sights give you a point of aim, but they don't let you know what it is you're aiming at. In my experience by the time the glow of the tritium really starts to make a difference I can't see much in front of me (though admittedly my astigmatism throws a wrench in that from the start). In low light they don't provide much added benefit at all, imo, as the tritium glow isn't that visible. That's why I've gone to fiber optic fronts on my pistols. For day shooting they're great, for low light (dusk/dawn) they pick up a lot of light (more than the tritium will cast by far) and by the time they're no longer useful because of a lack of light I can't see what I'd be aiming at anyway.
When it comes to handheld lights there are a number of grips you can use if you don't like one in particular.
http://www.thedailysheeple.com/why-you-should-carry-and-know-how-to-use-a-tactical-flashlight_072013. Personally I prefer the cigar hold/Rogers method but each has a purpose (one caution with the Harries method is don't cross your lower arm with your muzzle!). Handheld lights give you the option of searching with a light in one hand while keeping the pistol at a ready position, so you're not muzzling a family member or neighbor.
If fumbling with a light is a concern then you can always use a weapon mounted light. The biggest downside to a weapon mounted light is that you have to point the pistol along with the light, but you can always use the spill of the beam (especially with the output from weapon mounted lights these days) to illuminate quite a bit. Weapon mounted lights also give you a spare hand if you need it to help fight off an attacker or help a family member (i.e. carry or lead a child). You also have easier use of your support hand when shooting. There's also no reason you can't leave the weapon mounted light on the pistol and carry a handheld light, so you have the advantages of both worlds.
I find people tend to talk about using lights as if it's very difficult, but haven't really tried it. The great thing about using a light and a pistol is you can practice even in the daylight in terms of manipulating the light and the pistol together while shooting, and at night you can practice it with a cleared pistol in your own house and learn how the light casts. I know that most of us don't have access to night shooting, but you can break the task up into parts so you can practice the whole. I think if you can figure out how to do an emergency reload you can figure out how to use a light. I'm not saying you'll be a master of it, but you'll have the basics down to at least identify a threat (I've seen most people become proficient in an hour or so).
Of course, you can always go whole ham and have both night sights and a light. You need sights anyway even with the light (unless we're talking reflexive shooting) so make them night sights and then have a light. People seem to have a tendency of falling into camps of one or the other, without realizing there's no reason you can't do both.
Of the things I carry I think my light is by far my most valuable. I use it daily just around the house and from a liability standpoint whether I'm LEO or civilian I'm not pressing off a round without being able to identify what I'm aiming at. Lights are invaluable imo.