I don't quite understand what your trying to say here. This is exactly how GA works, you get a single engine endorsement (now called class rating) which lets you fly single engine aircraft (with some exclusions). All that is required is that the pilot is competent in operating the aircraft, there is no test nor training requirements (the onus is on the pilot to get the training they require). There are also Design Feature endorsements which may be required depending on the aircraft (61.755 lists what these are, IE retractable, tailwheel etc).
I think there is some confusion to what facthunter meant to say. People who can't pass a class 2 medical will not be able to pass the Driver's Aviation Medical (Recreational Aviation Medical Practitioner’s Certificate).
If you meet the requirements for the RAMPC then Yes you can get a Recreational Pilots License and fly with 2 pax under 10,000 feet, and won't need the Class 2 Medical. The catch being the RAMPC is not just fit to drive a motor vehicle, there are a lot more requirements in place.
I think one of the issues RA-AUS is trying to overcome are the pilots who have learnt to fly in a particular aircraft and then gone out and bought something different, have got no instruction and have been caught out on their way home with the new aircraft.
The onus should be on the pilot to get the training their require for a new aircraft, rather then a blanket rule. However history has shown pilots have not always shown the best judgement with more then a couple "incidents" on trips home after a new purchase.