Tidal forces. This is the biggy, If you are in orbit deep in a gravity well with a steep gradient then the orbital velocities of things 1m up/down from each other are significantly different. The material stength of any object extending over that 1m has to resist that force.
Those forces will rip materials to shreds.
Think of your hands being pulled up, while your feet are pulled down. The further into the gravity well you get the more up and the more down the two pulls get.
The only way to avoid the tidal forces are a straight in drop. But you can't do that as all around the well is a swirling gas field that will push you into an orbit.