I heartily agree with you that a flashlight, preferably a headlamp, is a very important article when treating a victim,but I don't usually stash one in my kits;I routinely have one as EDC nearly all the time. I prefer to think of a "FAK" as the sum total of the knowledge, skills and items that a responder or bystander will bring to bear on the situation.

For starters, I always carry four or five band aids in my wallet and a reasonably clean red bandanna in my left hip pocket. On my key ring in my right front pocket is a good dependable light (Fenix LD01). When I need to go beyond the band aid, I do have a formal FAK with Ace bandages, gauze pads, etc - about 8"x3"x5, weighing about 10 oz. And then there are ancillary items that can be used in a FA context - the aluminum stays in my backpack with predrilled holes that can serve as splints, for example, or the samll headlamp that I usually carry. This would include the stove and cook set I would typically be packing. Most importantly, I try and keep current in my training - I recertified in CPR for the umpteenth time a couple of months ago Fortunately I have a fair amount of treatment experience as a result of SAR activities - that is worth a whole lot of equipment.

More often than not when you are faced with a serious situation, you will be forced to improvise or adapt. Nurture that ability.