UCI approval only matters for racing, so I would be interested in something that is both aero and light. C4.0/C5.0 seems to fit the bill. While some might argue for running tubulars for race wheels, I'm not up for dealing with them.

From a business perspective, I see people running low profile alloy wheels or deep section carbon (generally, cosmic carbone or 404). The S2.0 is in line with UCI traditional wheel requirements and doesn't need special approval, so you have something that covers the alloy end of the spectrum. Where I see a gap is in affordable UCI approved carbon wheels.