Michael wrote:

The airspace classes are by no means an US national system.

No, other nations ALSO have bugs in their systems, but since I haven't
flown in those other nations I'm not too interested on commenting on
them.

You don't understand what I mean. Airspace classification is an
international thing, an ICAO thing. The worst a country could do is to
leave that international system. If you don't like airspace D, then your
approach should be not to apply it in the USA. I wouldn't comment on
that. But airspace D may have its place in other countries. In mine, it
certainly does.

Yes - it allows the controller to limit your ability to separate
yourself without accepting any responsibility for the resulting loss of
separation. That's a bug.

No. It allows a controller to provide some "big scale separation",
leaving the "fine separation" to the pilots.

It's only when things are made counterintuitive that problems come up.

Intuition is a very personal thing. What may be intuitive to you may not
be so to me and vice versa. Even more interesting, intuition can be
trained. When I started studying physics, quantum theory and realtivity
were the most counterintuitive things I could imagine. Today, they are
very intuitive. The same applies to certain aspects of flying.

Stefan