I can see a lot of potential with this plugin. If you were to implement permission nodes, this could turn into a full GUI of commands that all players can have access to, but certain commands are only visible with the permission.
It could also use vault to hook into an economy and allow players to use a command for a price. For example, a player could pay 500 to be healed through the GUI.
For a start, this is definitely a great plugin! I hope you continue development in it c: