It would make sense for the pilot to cancel IFR somewhere further back than the IAF, terrain permitting.
I dont see it that way.
I gave before the example of Southampton.
The IAF is almost overhead the airport at SAM, traffic would normally be positioned at 3,000 feet but down to 2,000 feet is available.
As I indicated earlier Pace's concern in this example of descending outside the ATZ and encountering weather other than as indicated by the METAR at the destination is not of concern. I would expect the cloudbase at the IAF to coincide with the METAR.
We all know the easiest way of positioning for both pilot and ATC are vectors. I cant imagine why a EIR pilot would want to cancel IFR before the IAF if a vectored "arrival" were available. In the alternate I also dont see why he wouldnt want to self navigate to the IAF with all the extra protection that would afford. In short what would he have to gain by making up an earleir descent?
So you would ask for vectors to the IAF and request a descent to the minimium available altitude. In all but circumstances where the METAR indiates the cloudbase is on the base of the IAF you know you will be visual, so job done so far as that goes.
I dont see this process would be disruptive to ATC or other aircraft.
It seems to me it gets a bit more complicated after you have pitched up at the IAF. What happens next?
If you are visual it seems to me you and AT have two options. You either continue with the procedure or position for some form of non procedural visual approach. I would have thought flying the procedure in VMC would make more sense in terms of fitting in with other traffic and in terms of ATC being better able to sequence the traffic.
If you are not visual matters are even less clear. Presumably the options would be to request ATC to reposition you for another go which might involve putting you in the hold (but are you entitled to be placed in the hold in IMC), or request ATC to provide you with vectors away from the airport towards your alternate with possibly an airways climb. Both seem to me procedures which are not well rehearsed at the moment by either pilots or ATC. Of course for the reasons given earlier this should rarely happen and only in circumstances where the base is very close to your minimium at the IAF.
It is for that reason that I suggested earlier it still seems far more sensible that if not visual at the IAF the pilot should be entitled to accept vectors to the top of the G/S and only if not visual at the top of the G/S would he be required to break off the approach. It seems to me this makes more sense because the aircraft would continue to be sequenced in exactly the same way as the rest of the IFR traffic and if a go around was required the traffic would simply fly the published missed in the same way as any other pilo breaking off from an IRated pilot's minimium DH.