1.I don't know how to do this with a lightsaber,but I do know that by using the light variables from rockets, you can add dynamic light to gun shots(I've said this before on other threads, but I'm, making a level with this effect. The lightsaber does, however emit a tiny amount of light (not nearly enough, it only shines like 1 foot). I agree there.
2.If anything stops moving, they don't stop instantly, remember inertia. Sometimes, though, in mp, I see people move around without moving their legs as if sliding for like, 3 seconds, but they have control. That may have something to do with ping, but I don't know.
3.Yeah, it is weird there, but humans have many ways of doing this how would the makers pick one?
4.I agree, but making a realistic breathing anim could be a little difficult and if constant, you could have an fps problem with entities more easily because you have so many anims happening at once.