Your suggestion has merit worth developing further @Stonecutter.
First thoughts are that the various School association and State and National Schoolboys selectors frequently get things wrong, and not all School Association Teams are of equal value. ISA sometimes have bumper crops as do CAS but generally the ISA II standard is usually at GPS Blue (3rd or 4th XV- there's not much between them standard) with CAS II slightly higher, and CHS II slightly lower.
Need to consider the bolter from the country, or a lad who missed on National, State or even association XV selection due to injury.
Interstate (quite a few former ACT players running around in Sydney Colts, not many Qld, Vic or WA) and overseas players (the very small exception rather then the rule) need some consideration.
It isn't about school leavers. Now that we have a mostly transparent and open selection process for State and National Under 20's players, which may include some late bloomers that the Koala Club overlooked or who were not flavour of the month with their school association, there should be some additional loading of points for those folk. It seems a bit of an anomaly that a lad selected to National or State U20's does not attract any points penalty until the year after they play, despite spending most of the summer and preseason in a quasi professional high level development programme.
Perhaps the Koala Club and Junior Gold Cup squad members should also receive a player points ranking, but most of the Koala Club attract points from selection at National Schoolboys.
Further to the point about Schoolboy selectors getting things wrong, there are occasions where a lad would otherwise be in Aust or State Schoolboys, but fails to be selected due a Loig player (with no intention of ever playing Colts Rugby) being a road block to their selection. Aust Schoolboys are not currently a formal development arm of the ARU and until they do become such, players intending to follow a Loig career after school (maybe only for the $ in the Carmakers Cup and for a Club to pay for their degree) then they should be eligible for Aust Schoolboys. I am sure that there were some damn fine Centres around who missed out on higher representative honours due to Tepai and Taane from Newington being selected ahead of them for State and National honours.
I think you need to look at it from both top down but also bottom up before you can start allocating x points for y skill level. How many player points do we have being generated by the "pathway" each year to be spread into 12 x 15 (plus fresh reserves) Colts 1 positions, and 12 x 15 Colts 2 positions (possibly into Colts 3 & Under 18s as well) - Top Down. Then look at the maths of assembling 12 teams that have the right balance of x Schoolboys, y State Reps, z Koala club/Junior Gold players, p School association 1st XV polayers etc to establish the demand for players and player points - Bottom Up.
To force kids to commute some distance to attend training with a distant club may require the peak body to pay them some form of compensation, or the kid may just decide to give the game up, and take the easy $ available from Loig in the Carmakers Cup, or just play socially for the local subbies club. I can imagine a kid staying in student Accommodation close to UNSW, USyd or Mac Uni being a little peeved to have to travel to Rat Park, Nepean Park, or Foreshaw Park when they could conveniently walk or cycle to St Andrews Oval, Latham Park, or TG Millner from their student digs. With the NSWRU and ARU on the bones of their backside, and most clubs operating on much less, who is going to pay for all the travel to keep these kids in the game? Many Colts 1 teams train 3 or more times a week.
Is there something we can take from the Eastwood model? They don't seem to have a particularly strong Colts programme, although it is competitive yet they seem to manage to roll out an impressive First Grade Shute Shield team annually. How does that happen?
Maybe rugby needs to borrow someone from the Horse racing with experience in working their handicapping system, or even the Bookmaking or acturiaral industry to come up with a fair and equitable system.