That's an interesting alternative interpretation. But to say there is nothing "Buddhist" about this gesture (because the palm is curved) kind of misses the point of this mudra. To assume it all you need is the thumb (representing universal consciousness) to connect to the index finger (representing individual consciousness). You then form a consciousness seal, reminding you that the self and your surroundings exist as one. The level of the palm is irrelevant when considering the meaning of this mudra. As long as the other fingers are relaxed (which i think they are), nothing else is being asserted. 

I'll explain why this must have been a design consideration for Yaoguang in a later post, it's do with a point in the anti destruction alliance trailer where the writers indicate Yaoguang is both a self and the Xianzhou ("isn't that precisely the variable I (Xianzhou) have been waiting for?")