You'll need to edit the plugin or run our awk script on it to find all the CBTxt API usages and translate the strings in "cbteamplugins_language.php".

We don't implement CMS dependency. If anything CB will become more distant and less dependent on Joomla with each release. We have our own language usages so we have absolute control over its usage. Joomla API changes too frequent for CB to utilize it to the fullest without constant re-writes with each major release of Joomla.

I don't understand what you mean by not user friendly. You're editing 1-2 PHP files verse Joomlas 10+ ini files (which are very hard to read). It's not user friendly to find new strings and add them from incubator projects, but that's why we provided an awk script (Google search for usage).

Yes, it's planned to improve this. Ideally we'd like database storage of strings and an efficient way to retrieve them, easy way to add more, and automatic addition of new strings. That's simply one idea we've had, but yes we're planning to improve this in the future.