Personally I think that the only decision to be made is if NSPR classes should or should not be added to AMHR Nationals. If they were to be added then I think they should be added according to the existing rules—an NSPR pony is an NSPR pony, regardless of whether it has an AMHR or an ASPC parent, and regardless of what size it is. If Nationals were to offer NSPR classes then they would be open to NSPR ponies, period. No size limits other than the maximum 14.2 hh specified by the registry. As someone already said, the NSPR division is not a part of AMHR, it is a separate division of the parent registry.
Normally I would say that NSPR classes should be added to Nationals, even though that really doesn't go along with the original intention of the division. After all, the division is open to half AMHR and even AMHR registered horses--and generally in other breeds the national shows do have classes for horses that have only one registered parent....the Arabians are one of the best examples, but they aren't the only one. They have classes for the partbred Arabians--and they don't restrict it--those partbred Arabians might be half Saddlebred and look it, but they still get to show as partbred Arabians. Perhaps the bottom line is that AMHR people really do not embrace the NSPR. NSPR is a place to register some otherwise non-registerable miniatures (i.e. those that are too tall for AMHR or those that have one parent that isn’t AMHR registered) and when NSPR was put in place for the half Shetlands, AMHR people wanted the same opportunity so NSPR was opened to horses of AMHR parentage as well. But, as soon as they are NSPR registered they are no longer anything to do with AMHR and therefore aren't to be included. That's why I said earlier that I think the division would be better left at Congress and the local shows that want to add it. IMO Congress is the best place for exhibitors that want to show NSPR and the best place to promote that division.
I'm inclined to think that NSPR should have been left just for ponies that have one ASPC parent, and not bothered with opening it up to AMHR. The intent was to promote larger Shetland bred riding/driving ponies and the registry should have just stuck with that plan.