both the aros cybergraphics api and sources are open,and compatible to cgx (de facto primary) standard, p96 is as well compatible to. so, we do have all material to start with actually. no need to open anything else.
While you would also control source code and the future development.
By the way, I took a quick look into AROS and it seems that graphics drivers are implemented separately from CGX (
https://en.wikibooks.org/wiki/Aros/Developer/Docs/HIDD/Graphics). CGX part in AROS is just cybergraphics.library (de facto standard for some sweeteners). The driver API is not CGX or P96 so nobody have to debate which one better.
Hardest part is integrating this stuff into the original, OCS bound, graphics.library.
