I'm very late into the game on this one, but if you're using a Weaver, you can temporarily grip the flashlight on the strong side of your neck to free your weak hand. This works even with my Maglite 4D cell but works best with my SureFire.
Rolling flashlight. Interesting scenario. One time in our room clearing training, the guy that was playing the "bad guy" rolled his flashlight out. Got OUR attention, so I guess it works both ways. Also lit up the room we were trying to clear while he hid in darkness in the next room. Bad stuff.
Light intensity. If you can get your eyes adjusted to have low light intensity to work for you, the same goes for the BG. So if you gotta shine a light, you might as well use a bright one. At least that way it'll stun the BG. This might sound stupid, almost Hollywood, but if you wear your shades just before you shine, it helps.
IR. Wish I had that kind of money, but yeah, I guess that would solve the whole thing wouldn't it?