Yea, it's sort of the wrong place, and it has sort of already been done. Although it's relevant to Gen V, the Unova Region forum is primarily based on discussion of the Gen V games, rather than community activities. For uses with friend codes, feel free to check out the entire trading forum
or the seemingly underused battle thread
An index of friend codes is mostly useless if there is nothing to do with them. If you need to trade or battle a user, then the arrangement should probably have come from one of the above links if it exists on the forums. If for some reason you need another user's friend code specifically, and aren't arranging a trade nor battle with that person, then you should use private messages to exchange information.