That's pretty much the space Wordpress thrives in, isn't it?

How shit the product is for Wordpress is a matter of debate, but the documentation and ecosystem around it is robust enough to make it fairly easy to hack and use/abuse to do what you want it to.

This is true. Docs, re not necessarily considered important features of the product itself but they make a huge difference.

Other things that I pay attention to are built-in integrations with other tools, the ability to import and export data, familiarity to users, similarity to existing tools, tutorials that leave users confident, and documentation with examples of use cases are all similar factors.

And if your project is open source and the docs are clear and show good vision, you might even attract folks to come fix your broke-ass code :D