A better faucet

Lever type faucets have the problem that they are not very controllable initially, so people can get a rush of water that is too hot or cold.

Most lever faucets also control temperature and they also can have a narrow range of temperature transition, so any solution would need to deal with that as well. For ball faucets, the CNCing of the hole shape could be adjusted. For ceramic discs, the shape could be changed. Either of these would require only changing the profile of one part, making it easier to iterate to something that makes it easier for people to smoothly turn on and control temperature without increasing manufacturing cost.