Enjoying your plugin! It appears compatible with core stuff by Visustella, as far a i can tell.
A proposal on what could be added:
Since my actor can equip 4 skills simultaneously, it would be pretty neat if the second skill he ever learns gets added directly to his equipped skills without having to go into the menu and choose/activate it.
For example, the Pokemon games are doing this, always checking whether theres space for a new learned skill and if yes, the part of equipping it gets "skipped".
Maybe theres some simple way doing this that i havent discovered yet, but otherwise, this would be my suggestion.