Luke got sucked into a tube in which he slid down to, not the end of the tube, but some point in the middle which happened to have a hatch that then dumped him on top of one of Cloud City’s antennas. That’s a pretty crappy waste disposal system. Imagine all the broken antennas, and all the crap that didn’t slide down and land precisely on that one hatch. Where does all that go then? To another antenna somewhere else? No, I have to strongly disagree, it is a very “bizarre thing,” that is if you have to attribute some engineering logic to it, which you really don’t. And if it does have a purpose, than I doubt that waste disposal is the answer.
FTR, the middle of the tube dumped him into a second tube, which then dumped him out to the antenna.