A single physical USB device can enumerate as multiple virtual devices. This lets you easily side-step the limits *if* the game supports input from multiple controllers at the same time. The games I use controllers for allow you to map to multiple controllers, mouse, and keyboard, all at once. The touchpad could simply enumerate as a HID Touchpad. Apparently Windows already has a Touchpad Haptic HID Profile even.
Honestly, if Valve is making you require Steam to fully use the Steam Controller, that's disappointing because, as far as I can tell, nothing it's doing can't be accessed via HID usage.
A single physical USB device can enumerate as multiple virtual devices. This lets you easily side-step the limits *if* the game supports input from multiple controllers at the same time. The games I use controllers for allow you to map to multiple controllers, mouse, and keyboard, all at once. The touchpad could simply enumerate as a HID Touchpad. Apparently Windows already has a Touchpad Haptic HID Profile even.
Honestly, if Valve is making you require Steam to fully use the Steam Controller, that's disappointing because, as far as I can tell, nothing it's doing can't be accessed via HID usage.