the issue is still open, and for good reason. whatever excuse they may have, the current HTML output for lists is not idiomatic, and their suggestion is essentially to use CSS hacks to fix the problem. sadly the AsciiDoc version with the problem is the one being used by GitHub itself. So until the issue is properly fixed, a new version pushed, and the new version accepted and put into use by GitHub, I am not interested to switch. This could all happen in a week with the proper motivation.

I am not sure what the worry is with backward compat. The only difference with the resultant HTML, is extraneous "p" elements would be removed from "li" elements. Anyone who has been relying on that behavior, has been relying on non-idiomatic HTML and should be inconvenienced.