I definitely prefer CS's set up from a gameplay perspective. Nothing quite matches the feeling of excitement you get when discovering a powerful quartz, and CS2 has bit of this too with the
Characters ironically feel more unique in practice in the sense that there are more kinds of Quartz, and you often have to choose who gets what (compared to Sky, which is more standardized with its distribution). You'll usually have that one character who has all of the amazing offensive arts, your domination user, your delay king, etc.