Many of the posts in this board relate to multiple categories, for example: announcing a mobile or React-related package, looking for help with testing, etc.
I think that using something like the official Discourse tags plugin will be beneficial. It will also be possible to create tags that will provide more granular metadata, that would not justify creating a separate category for.
Let us know if you have any further questions about the Tags plugin. Tags are easier to use poorly than categories. meta.discourse.org for instance isn’t the best example of tags in action, since we prioritised experimentation over strict conventions. We recommend limiting their use to very specific purposes, which it seems you’re on to already.
Anyhow, when you’re done evaluating it and ready to have it installed, let me know!