If only some of the plugins are available, support only the commands that can run with the currently available dependencies. May want to add a guid to the PLUGIN_PLAYERDATA_NAME to prevent chance of large iteration to search for my plugin every time I read metadata.
Does performCommand need player permissions? [Yes it does]
class BlockMined(private val oreCounter: HashMap<Strig, Int>) : Listener { Tut tut tut! Use a normal map! In fact you should probably just pack it up in the user metadata instead.
Table dispatch Look in code complete for entering program logic as data Dagger and dependency injection.