Your rules for fanning need to address two points:
1) This action requires two hands. As written, you simply can't use an off hand weapon, but in reality you can't fan if you only have one arm.
2) AFAICT, you don't currently have a restriction in place to prevent fanning in melee. I'd strongly consider putting such a restriction into place.
I'd also suggest that rather than a new Talent, perhaps fanning could be a specialized use of Sleight of Hand?