Exactly BH. If we had 10 teams of required standard, they would be presently playing in the NRC. But 9 was too many and has dropped to 8.
I've only quoted your post BR as it gives me a starting point. I've just read this entire thread and have drawn upon the ideas of others to come up with this. Back in the day the progression for a player was club - rep side (city/country) - state - Wallabies. So it takes on a bit of that traditional approach.
The main problem with the NRC is that 30-40 players who are in the Wallabies squad are excluded from playing (by and large). Inject these players into the system then it not only increases the interest in the competition but also the depth of the player base, and 10 teams is sustainable for a domestic competition (3-4 Wallabies go to each team).
It goes something like this (I'm mainly looking at it from an Aussie perspective):
1. Feb-May - a 10 team NRC comp in Australia is operated whilst the 14 team M10 comp is taking place in NZ. (SAF/ARG/JPN do their own thing in similar formats, CC obviously in SAF). 2 of the Aussie teams are aligned with each of the existing Super Rugby franchises.
2. June test Window includes Bledisloe 1 (except Lions years)
3. July-September - each of the 5 Super Rugby franchises selects their 32 (or so) man squad from their 2 NRC sides, those not selected go back to club rugby. The same thing happens in NZ. Each team plays every one once so comp goes for 9 weeks then 2 weeks of finals.
4. October-November -TRC but only play each other once plus Bledisloe 3 (or 1 & 2 in Lions years). Maybe during this period a Super Rugby franchise less the internationals play the curtain raisers as a development type thing e.g. the Brumbies play the Stormers at the Capetown fixture.
5. November-December - End of year tours.