When I said "equivalent aircraft" that's exactly what I meant - ie fourth generation fighters like F-15, F-16 and F/A-18.
I also do not know the AAR onload rates of the latest American fifth+ generation fighters, but I'd wager that they not as puny as that of Typhoon. US aircraft have consistently demonstrated a better AAR onload rate when compared to those of European origin. For USAF aircraft this is probably explained by the inherent nature of the boom system, where the high flow rates must be properly utilized to minimize the disadvantage of the single dispense point. USN aircraft also exhibit much better onload rates than other probe receivers and I would guess that the nature of blue-water ops, using an single-point emergency terminal tanker, causes the AAR characteristics of their aircraft to assume greater significance than it does to Europeans.
You have alluded to a specific reason for Typhoon achieving such a low rate, which I think I have already heard about. However, this reason seems to me to be another example of designers coming-up with a clever solution for one specific scenario, which then proves to be a limitation in many other ways. Another example of this kind of thinking is the omission of an ILS system from some military aircraft in order to save weight. I can only imagine that the basis of such an idea was that all-weather recovery to military bases would normally be achieved by GCA or other methods. Of course, in the real world, such aircraft often need to use civilian airports or foreign military bases where ILS is the primary aid and are forever handicapped by the narrow view of those involved in the original procurement.
I don't believe that the low AAR rate is in any way a significant enough factor to be regarded as Typhoon's Achilles heel, and hope that the underlying reason for it does indeed give the aircraft many other advantages. However, the fact remains that a low AAR rate can only be a weakness and is clearly something that has been compromised in this design to allow priority for other characteristics.