If a hobbyist really wants to "compete" with Z-Wave, IMO the best course of action would not be to develop a new standard, but rather to
continue the reverse-engineering work and produce an interoperable (yet open-source) Z-Wave implementation on CCxxxx or other commodity wireless hardware. This would be of immense value to the community, and a great way to "stick it to the man" at the same time. I also think it is quite feasible, with the exception of the secure/encrypted aspects, which most off-the-shelf devices don't (didn't?) use anyway.
Also, here's the xkcd cartoon referenced above, in case someone didn't catch the allusion
https://xkcd.com/927/