[Raydeus]

I have an idea. What if SE made it so merits were interchangeable within their category, but could not be moved to other categories? For example, somebody who has a PLD and a BLM could alternate their merits between Enimity- and Enimity+ as needed, without suffering any penalties, but they could not take the Enimity- merits out of BLM and get Thunder Magic Potency.

That idea has come up before (specially in the ask SE section). And we are still waiting for it to happen.