Just maybe we have got the wrong idea? Back in 2014 London/Heathrow changed from Class A to Class D. Seems to give them much added flexibility. Class E has been used for many years in the USA and pilots and controllers are used to it, whereas Class E in Oz is a much more recent addition to the airspace menu. I am still not convinced that the pilots it is designed for (VFR) know how it should work or how to participate in it. It certainly has a role, but the very small amounts and the failure of related pilot education makes it that much harder, which of course it isn't. In the US, I suspect that VFR pilots fly more in E than they do in G. Some talk to the controller, whilst others turn the music on! A very different culture!
CAA approves reclassification of airspace around London Heathrow - Airport World Magazine