Would allow the user to specify an amount of experience to be taken from the player similar to the way it currently works with the set command.

Example: /exp take playerName amount

EDIT: Realised that you can do it by making the given amount negative, but I still think this is a good feature and possibly something to look in to.

(responding after your edit)

Not sure why we would add this with being able to give negative. It works the same way the money command works.