Well the whole point of SOMETHING falling is to just establish dramatic effect. Like "Dude! Luke's super high up hanging on to that upside down antenna thing cos we saw that thing drop to who know where!" In this case the ambiguity comes with just one blurry object falling which people would naturally assume is Luke's hand/lightsaber because it was the only other object that fell off the same remote area which possibly establishes continuity as to what happens to the hand/saber.
If it's one random object then there will be speculation forever as to what the heck it is. So why not make it multiple piece of debris establishing it's just some random crap being ejected from Cloud City? Sneak in the hand with saber in it for the fun of it and so everyone's happy. =D