That actually seems similar to how we do it. 4 levels represented by a coloured sash, 3 of those 4 levels divided into 4 sub levels. Each of the 3 levels corresponds roughly to 2 of the 6 forms. 1= Sui Lum Tao and Chum Kue, 2= Bui Ji and Wooden Dummy, 3= Pole and Knives 4= You have learned the forms and are now making the system your own.I think your guys are right about wrestling and boxing being problematic to add a belt system to... and that there really would appear to be no benefit.
From my (admittedly limited) Wing Chun experience, it doesn't need belts... but they in no way seem incompatible.
The WT school I went to had no ranks... but students were divided along which form they were learning.
- Twice a year, they would accept a new group to begin learning 1st form (Siu Lim Tao). This seems like an obvious 'White Belt'.
- Should you stick it out for a year or so (I moved away and couldn't keep going) they'd start teaching 2nd Form (call that Blue belt).
Then there was 3rd Form and the dummy form. (Purple and Brown belts?)
After learning them all and being judged proficient, that's an easy parallel to black belt... and like BJJ, there (to my knowledge) isn't any formalized curriculum after that. Lineage and time in rank form the basis of higher Dan ranks.
Again. No arts really Need belts; but all in all, the WT curriculum doesn't seem so incompatible to me.
When I teach people the material only conforms loosely to that though and follows more when I figure when they are ready for new stuff. The grading system is really just for everyone to keep general track of what we are doing.
Laughing at wing chun done with a grading system and sashes/belts I think is just a bit of martial arts hipsterism. After all, go back before the 50s/60s and wing chun was never taught in schools open to the public, then Yip Man started teaching it like that. But the idea of a wing chun school never seems to bother these people, just a piece of cloth hanging around someone's waist. If people are too "real" for that, so be it.