Backpeddle a bit...Smith
you have a different view? D over D?
Class D from the ground up to overlaying class C...thats a big class D zone! However, does it work. ICAO D, clearances required, separation IFR from IFR from VFR from VFR. Approaches protected...doesn't need radar to be effective. No need to retrain ATC to handle procedural E...
and a lot less heartache
OK, what's the down side? My experience with EN tower charges has my wallet wincing...then again EN is a C tower.
All things equal radio and transponder requirment s the same...already trained up to handle procedures for ICAO D so thats a win...ARFOR, there must be a gotcha.