The commonality with NATO platforms is irrelevant
Completely disagree. The E-3A and E-3D are both tasked by NATO and have the same capability to the extent that either type can be tasked to fulfil the tasking requirement. Its all part of the agreement that UK has with the NATO AEW&C Force. The NATO AEW&C Component are not involved with tasking - that is done by the NAEW&C Force Command which is the tasking authority for both the Waddington and Geilenkirchen Components. Not withstanding that the NATO E-3A has a new updated software "back end" of the mission system, the main sensors are the same (although the ESM systems are different) and either type is interchangeable when it comes to tasking. Tanker availability is a main player during live ops, and the fact that the E-3D can take fuel from a boom tanker is a huge advantage because otherwise a drogue tanker would have to be tasked in addition to the usual boom tankers leading to a loss of flexibility (and yes I know that this capability came about by default, but it has given us major advantages during both NATO and other coalition ops).