Well, if you think I'm going to descend in IMC to 200 ft offshore 'hoping' there are no obstacles in the way, you have another thought coming! The example I used was just one threat - there are plenty of large 'hard' things that populate the sea and are not notified.
Regarding the SAC Rig Approach procedure, I'm not sure that it does require a design for each platform. On the contrary, I believe it is simply a means of flying a modified OSAP or ARA but with greatly simplified pilot inputs and greatly improved automated functions. The pilot enters the destination rig into the FMS, then sets the inbound course on the Flight Director using the wind direction and obstacle environment as factors. The MDH is set along with the required offset and then the system computes the flight path to arrive at the FAF from the enroute phase, and comences the descents and decelerations as required to the MAPt - based on range/offset distance .It still requires the Radar for obstacle clearance, and indeed displays the required obstacle free sector on the Nav Display. It is still undergoing certification flight testing.