terspter,
Completely agree...
the FAA went for quantity, not quality.
The concept and reliance on idle descent as a selling tool, alleged fuel and track mile savings was a big mistake, when the airline figured out it didnt save any fuel, and RNP vs non-RNP traffic was not easily blended with current ATC toolset.
SW spent quite a bit of money upgrading their fleet, training, and the OpSpec took about 3 years to get...all that a no place to go.
All that is really necessary is to install the standard T" or "Y" configuration, use 4 mile TF legs instead of 5, then transition to 4nm radius RF turns once the pattern is established.
Simple, effective, straightforward for cert and application.