I would add some things to that:
- If it is a module that works with network stuff, the module must support IPv4-only AND IPv6-only AND IPv6/IPv4 dual-stack systems. Missing IPv6 support is completely unacceptable in this day and age.
- The module should NOT force me to use it's own event loop. In 99.9% of my use cases, i already have an existing cyclic executive.
- A usable changelog or some other sort of "we change xy in version xy" is a valuable bonus. A proper, read-only version control system is even more helpful. I don't care if it's git, mercurial, subversion. Heck even SCM is better than nothing. Basically, if something breaks after an update, i want to be able to find out what the author(s) have changed. Manually written changelogs might or might not be complete or correct, access to the version control of the source code as a last resort can come in quite handy.
