I imagine it would be too difficult for these devs to implement an actual traffic control (queue) system that gives each individual ship clearance to enter and exit.
I never like the aspect of these large ships having to enter the mail slot. When first playing the game and getting accustomed to landing, I had imagined these larger ships would be dry docked externally, with an umbilical attaching to the side of the ship - or wherever the primary hatch would be located. I imagine the landing sequence would be automated partly, similar to the way an SLF docks with a mothership.
the ships we currently have are not very large compared to the mailslot.
there are like SUVs ...
now imagine driving your SUV through a totally normal toll gate with 360 km/h... (=100m/s)