Big fan of RDM since Final Fantasy I. I believe other fans of the lore would agree that there are three principles that lay down the foundation for the job. 1. RDM can cast white magic. 2. RDM can cast black magic. 3. RDM wields a sword/rapier. It looks like you got the three principles covered. That being said, it is very interesting that you've given this healer two DPS classes as its crosses. I don't see an issue with it though so long as it has innate abilities that are mandatory from CNJ. What this does though is makes it potentially fill the WHM slot, not SCH. What I like about this is the potential to balance and complement AST much like WHM/SCH.

One issue I see is Scathe is a level 15 class quested ability. Like Fluid Aura and Aetherflow, it is very exclusive to the class. Thauma's are an unstable and destructive lot, and I think it best not to ruffle their feathers Giving RDM Swiftcast, Thunder, and Blizz 2 will do wonders. But I would practically play this job for Remedy alone. AoE regen and cleanse? HOMG, give me now!