''AI saw a commercial advantage for the CDL entry. ''
Possibly, but the FBW Airbus designs have so much low speed protection, they and the regulating authorities don't consider the risks significant.
''No performance problem operating without them with stall-related penalties. The concern relates more to what happens at stall ... one presumes that the stall characteristics of the A320/1, with asymmetric chines, are relatively benign ?'''
The A320 series is unstallable in normal law.
''I don't think one would expect to see any noticeable (to the pilot) difference regardless of what was missing ... other than in the stall regime.''
As above. You can't stall it in normal operations. In Alternate law, the protections are replaced by a stall warning at 1.03 VS1g. I don't know if the stall characteristics aren't affected, or the it wasn't considered significant - or if the margin takes a missing strake CDL into account. The instances of going into alternate law are very rare. And the crew will have aded the 5 knts to VApp for added protection anyway.
''A quick looksee through the FAA MMEL doesn't immediately show an equivalent MMEL provision. What does AI term the devices ?''
'Nacelle Strakes'. And they are a CDL (Configuration Deviation List) item and not an MMEL item.