While kernel support is the first step, userland applications need to take advantage of the hardware for it to be useful. e.g desktop envoronments need to care

While kernel support is the first step, userland applications need to take advantage of the hardware for it to be useful. e.g desktop envoronments need to care for how it interacts with touchpads, you want your wireless interface to actually be configurable. You want sane handling of which audio device is the default, and you'd want recognicable names to select them. The list goes on for another mile.