Even 35 years after the Air Force Board decision of 1968 was reversed, it seems it's still necessary to explain that it was brought about in an attempt to rectify a persistent undermanning situation. (If you have Jeff Jefford's "Observers and Navigators," you'll find it explained at length on p 219.) It was originally aimed at both VC10 and Comet fleets - but with so few Comets in service, and that service terminated in 1976 as the Transport Force was reduced by 50%, it became effectively something that was seen by the world at large as something exclusive to 10 Squadron. (It's a mystery to me still that the decision was never applied to the V-Force.)
As a retention measure, it was almost certainly a failure and, regardless of its intentions, 10 Sqn captains took their share of the post-75 compulsory redundancy scheme aimed primarily at 'reduced forces.' The impression that was abroad amongst most of the Service as a result of the decision was by no means lost on successive Sqn COs but, as it had started as an AFB decision, all attempts in the 70s to have it reviewed were rebuffed accordingly. Circumstances must have changed by 1980 when the scheme was rescinded.
And as it happens, the Specialist Aircrew scheme grew out of the same undermanning concerns of the later-60s. History may record that idea as having attracted wider popularity.