Personally I like the default method of Flashlight use. Game loses alot of its intensity if you cheat using another method.
However I think it would be cool if it was a military flashlight (L shaped) with the pale red light (max distance like 20ft). You could have that in the opposite hand for Pistol, and rather than attach it to the weapons (since its L shaped) it would clip onto the armor on your chest. Uses battery power, say there is like 1 battery every 3 or 4 levels, so you have to use it sparingly. And two handed weapons get lowered while you are turning the flashlight on or off.
This would maintain the mood of the game and make alot of people happy. Its a rather ambitious design approach and far to late to implement it now since the losers are going to be after the mods with bright flashlight that is on 24/7.