The problem with such an approach (no pun intended) is that yet again it will not work with the existing ATC framework - which simply operates on the basis that the pilot has the privileges for the published approach.
There will never be any mechanism in place for anything different, not least because nobody will ever be able to prove at which point the pilot became visual
Neither of those are an issue. ATC does not depend any "single published" minima that all pilots must have the same privileges for - they cope with a variety of operator-determined minima that ATC will have no idea of. ATC/ATIS report the conditions, the operator determines his minima and whether he can accept the procedure and when/if he has to go missed. The list of operator-specific factors that modify the published minima is endless - everything from company limits on procedure types, to weight and conditions determining climb gradient on the MAP to crew currency on a specific procedure, to stabilised approach criteria which mean that ATC can never know for certain, given reported weather conditions and the published minma, whether or not a given aircraft will complete a given procedure.
The IFR system currently works without any mechanism to prove at which point a pilot became visual, so why is this a barrier to any other method?
The actual barrier to an intermdiate IR being meaningfully easier than a full IR is that making the departure and approach minima a bit more restrictive doesn't meaningfully change the Theoretical Knowledge and Flight Training and testing requirements from a full IR.
brgds
421C