Which mage class is worth to invest empress set on?

Lumi is kind of OP now (all new classes are OP anyways). I don't know if it gets nerfed to dust like DS though, so its a risk.

That would be a 'No' if we base it solely on KMS' Luminous nerf but I do think that it's no longer safe to plan solely by that seeing that CMS' Angelic Burster is already being nerfed even worse than her nerfed KMS counterpart before being released. I would say that if the OP is concerned about that BaMs would be a better choice because they've only been made better and better.