Experience storage standard feature in many mods and it would make sense to bring it in into TC by improving the Brain in a jar. This would make jarred brains a lot more useful since they can even be picked up and store up 30 levels worth of experience. It would also play nicely with the experience augment. It should be some form of addon block to the jar, maybe some sort of brain-washing machine? (Experience levels are in knowledge in thaumcraft lore). This could be extended further to make a research machine that makes theories out of experience, but thats just a random idea.

It could be unbalanced, especially if combined with the headband of curiosity, if its too unbalanced, lock it behind extensive research/impetus. If it doesn't seem too unbalanced, this would make the headband of curiosity more viable research method with the experience loop.

I think a way of preventing of using the experience loop would adding some punishing mechanic eg. storing xp directly into jars causes warp or flux. Causing warp would go perfectly with the theme of "brainwashing" if that theme is chosen.