If the tunnels intention was to throw everything out, why didn’t it end at the bottom of Cloud City? Why was it necessary to have another tunnel in the wall that opens conditionally? We don’t even know what triggered the hatch to open, was it Luke’s weight or was it just bad timing (just like it was bad timing that the trash compactor starts with our heros inside)?
A lot of discussion to skirt around the obvious: That Maz having Luke’s original lightsaber is silly.
I think it would have been a better idea to have Rey find the saber whilst scavenging junk, rather than the Maz scene which was purely a device to bring a saber into the narrative, Maz giving Rey the magical gift (transference).