Suggestion that will be ideal for modpack devs : Allow the gui screen to appear through the pick a class command.

[Jonah-Thomas]

The reason for this is lets say you wanted to utilize PMMO, Origins, etc. the only time a player will see this gui is when they are trying to change their class for the first time upon entering the world which is something not all modpack devs would like. Well done on the system as a whole.