> Would you rather have it degrade to the functionality of an Xbox 360 controller without Steam?

Yes? What's wrong with that? Then it's at least usable.

Usable sure, but then why did you get a Steam Controller if not to make use of the additional inputs?

Not really. Can't really map a touchpad as an analog stick. Can't map a gyro as a joystick. Can't take XBox rumble and map it to the Steam Controllers haptic feedback.

Can you hack it together in theory, get something working but making sacrifices left and right? Sure. But why would Valve want to do that? Use experience would be incredibly bad.

But give it time. There will be a standalone driver for Windows eventually, either from Valve or from the community.