I'm curious to hear the answers to the questions Luke asked earlier. I also read through the documentation and wasn't convinced it was thought out well enough to actually build something on top of,

There are many colored coin protocols in use. OpenAssets is probably the most popular one, but it has many critical flaws IMHO.

https://github.com/bitcoinx/colored-coin-tools/wiki/OpenAssets-deficiencies

but there's no reason it can't get a number as a work-in-progress.

The protocol is not a work-in-progress, it is already in use, you cannot change it without breaking stuff.

The doc can be improved, though. There is a lot of fluff but the actual important stuff gets just few ambiguous sentences.

I hope it does continue to get worked on, though. The lack of response or discussion worries me that it might become an abandoned project.

The original author, Flavien, have abandoned it, he now does a private blockchain thing, OpenChain.

There are others who still use OpenAssets, e.g. Nicolas, but the protocol can't be changed.

There are other colored coin protocols in existence/in development, though.