3rd Party Plugins being off topic has been a hot button for years. Every time it's discussed on meta (which is usually once a year) there is a bundle of problems that come up which don't have optimal solutions. Some (not all) of these issues that come to mind are:
- How do we separate premium plugins from free repository plugins?
- How do we separate premium plugin support from open support?
- How do we handle authors who want to dump their support to WPSE? I.E. How do we prevent authors from abusing the site and the users here volunteering free support?
- How do we handle version changes of plugins?
- For example, WordPress Core rarely has mass code changes because of backwards compatibility. WooCommerce on the other-hand deprecated a literal ton of functions and methods in v3.0. Many pre-3.0 questions would no longer be valid or helpful but it would be difficult to tell based on the question content itself. Many questions dont definite what version plugin they're running, neither here, SO, or the forums.
- With the influx of plugin related questions, how do we keep the Q/A ratio from plummeting?
- Closing poor questions, non-development related questions, and actually answering questions helps keep our site and QA ratio healthy.
- With the influx of plugin related questions, how do we keep janitorial duties ( spam-busting, closing of actual low-quality questions, edits to keep questions in good form ) from getting out of hand?
- There are currently
54,891 plugins on the WordPress Repository. How many have a decent documentation? How many don't have any documentation at all?
Many, I would almost say most, questions regarding 3rd party plugins are either non-development related, very low quality, or "do this for me" which are not good questions for StackExchange.
I also do not think we can treat any Autommatic supported plugins (WooCommerce, Jetpack) different than the rest of the plugins repository, in my opinion it's an all or nothing change. Otherwise, it's not fair to the community as a whole.
It would be fantastic if we could open the site to all 3rd party development questions in theory but I feel in practice there would be many hurdles, not enough experts, and too many low quality questions to sift through. Simply put, in my opinion, WordPress Core is a much more manageable scope than the WordPress Ecosystem as a whole.
I think to overturn the rule of plugins being off-topic we would need to find creative solutions to the issues above. I personally do not have good answers or solutions to the problems stated above and can see them getting out of hand quickly. That is a problem.
I believe it really comes down to Logistics. Are there enough experts to active in this community to keep up with the influx of plugin based questions?