The E3 does have a probe for AAR from RAF tankers but... It is not allowed to use the probe to refuel from other coalition tankers. For example, it uses only the boom behind USAF tankers. Does that mean that RAF and NATO E-3s retain the probe ONLY to maintain compatibility with the RAF's centre-line hoses and, if so, at what cost? The USAF E-3s don't have a probe of course.
IMHO the best compromise on the tanker is a recepticle for rcvr AAR, a boom and 2 wing pods. And if you have money to spare - add a centreline hose for redundancy (and legacy heavy rcvrs).
The absolute worst case scenario for a tanker platform would be wing pods only, no rcvr capability and leasing it through a PFI with a non-negotiable contract covering 27 years. I'd rather hang AAR pods under the bellies of our fast jets and let them buddy refuel each other.