You are correct I what you say until you get to the bit about the nose wheel steering disengagement from the rudder system, it does not ! The nose wheel is steered by a single rod attached to the rudders by a springs, as you move the rudder on the ground the springs apply force to the nose wheel via the springs. When the nose leg is fully extended a cam engages the nose wheel centering lock ( it is attached to the rod that runs from the bottom of the sliding part of the leg ). When in the air the rudder is still attached to the nose leg in the same way but operating the rudder just compresses the spring because the centering lock prevents the wheel from moving. I suspect part of the reason for this system is to stop over enthusiastic rudder inputs in the air, the aircraft is well balanced and the only reason I can think for using full rudder to recover from an unintended spin ( the aircraft is not cleared for intentional spinning ).
Now back to the problem, the centering lock on this aircraft stays engaged on the ground because the aircraft settles at the wrong attitude after landing, the reason for this is incorrect ( or lack of ) servicing of the shock struts. To put the aircraft in the correct ground attitude the correct spring rate is required, this is a rising rate system so it is critical that the correct amount of oil is in the leg along with the correct pressure. If you think that just sticking a bit more pressure in a leg that is low is the answer think again...... you will not get the correct rate rise.
Likewise putting too much pressure in the note shock strut to get a bit more prop clearance is a perfect way to create this problem.
Until people grasp the theory of rising rate springing and the fact that this leg requires more oil than American leg they will continue to have nose wheel steering problems with the Robin.