Surely UAVs would only be useful for a few mission types, two way data links are not very covert when you want to sneak about. UAVs could always gather data covertly for post flight analysis, but
AFAIK 51 is well respected due to their operators timely dissemination of info, that can't be done post flight.
What about converting two or three of the E-3Ds to ELINT and keeping the spare bits for the rest of the fleet, still leaves four or five. Then get something smaller (Global Express for commonality?) to complement it for the jobs that don't require the whole capability.
Never understood why we keep in squeezing all that kit into a Nimrod, apart from the RAF always doing it the hard way!
I seem to remember the US were going to put all their eggs in one basket at one point with the E-10, how would it be in 2 places at once?
http://www.spyflight.co.uk/767%20mc2a.htm
But it seems to have been canned, talk about HVAA. Think the USN is looking at MMA or a divertive.