In addition to the confirmed hidden effect being DEX +6 (Master). Based off my personal experience another possible hidden effect may be Reduces "Overload" rate, more testing required. Since using this animator I hardly overload, almost never! I don't even use the other Overload reduction gear in between using maneuvers, and believe me I use a lot of maneuvers all the time. I could just be incredibly lucky, nevertheless more testing required!
Likely to have hidden effects on both the master and the automation. I imagine it'll be a substantial HP/MP Boost to automation, frame allowing. That is, if the animators are using a linear system.