After spending some time as a faery sage I must say I'm glad we opted out of the build here in TVK. In my experience the lack of mana is a heavy burden despite my hybrid success. I could see its utility but feel the faery excels at it's t/m capability with mystic and rogue. Both have proven to be effective game changers and they both benefit from land efficient personalities. Sage is best when all faculties are in play I guess we all know, but in actual play these benefits are more apparent. This is my first age ever playing sage so ymmv.
Edit: the good thing here is that TVK is heavily influenced by player input. Ethan has shown interest in faery sage.