Unless I'm missing some USA specifics (if so, please correct me):
Class D airspace is not an FAA concept but rather an ICAO definition. It
seems to me that you should sit down and re-read the airspace definitions.
Class D: *No* separation provided for VFR flights.

Right -- there is no separation provided in Class D. And no one should
expect the controller to maintain separation.

This is precisely my point, which may be summed up thusly: Class D is
"pretend" controlled airspace. It should be regarded as "Barely
controlled" or "Semi-controlled"...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"