The Black Buck raids needed so many tankers because:
1. The Vulcan burned about 3 x times the fuel per hour that a modern fighter-bomber requires.
2. The Victor K2 had a relatively small offload capability compared to its own fuel burn rate.
3. The Vulcan was using dumb bombs and unsophisticated bomb aiming equipment, so to stand any chance of hitting Stanley aerodrome, needed a large bomb stick.
4. Down-track RV procedures were difficult, relying on very accurate navigation and A/A TACAN. Hence an accompanied cruise was preferred.
Were it to be necessary ever to repeat such a mission, a single Tornado or Typhoon with an appropriate, very accurate weapon would need far, far less fuel. Modern tankers carry HUGE amounts of fuel; the Voyager carries around 40 tonnes more than a VC10, a difference which would keep a Tornado airborne for another 20-ish hours...
As for AAR consolidation, that's fine if 'hoses in the sky' is not an issue. Otherwise having a single tanker with lots of fuel and only 2/3 hoses is perhaps of less worth than 2 tankers with less fuel but 4/6 hoses in the sky - and which can be in 2 places at once!