I think it would be useful to integrate with PlaceholderAPI from the get-go to support placeholders for messages and other plugins using this. Things like translations and message systems would probably be able to use the api quite effectively, and I’ve gotten it to the point where it would only be a few lines of code on your part. (I could contribute the code myself if you would prefer).
Another thing I think might help would be a GitHub repo for this project, especially during the starting phase; that way people can contribute faster and provide feedback more directly to the code you write.