Maybe I over-looked it, but I cannot find where this card is not legal as of right now. If you look at the DCI Floor Rules, it reads:
604. Authorized Models, Stat Cards and Terrain Maps
All Star Wars Miniatures models released by Wizards of the Coast LLC are legal for tournament play. Players must have the official corresponding stat cards for all registered miniatures. Players using multiples of the same model need only one copy of the official stat card for those models, but still must provide a clear method for all players to readily know the status of each individual model. Players must make their stat cards available to opponents or tournament officials upon request.
Stat cards are interpreted using the official Star Wars Miniatures Game Rules and Official Errata. Errata can be found at: www.wizards.com/default.asp?x=swminisAt one point I believe this stated printed stat cards are not legal, but it does not mention that in any way now. It only stipulates official stat card, which the Elite AT-AT Driver is.
Going further, the newest Rule Book (Clone Wars) makes no mention of stat cards beyond the description of how to read it. The Errata also has no mention of official stat card, but does define Crack Gunner #, which only shows up on the Elite AT-AT Driver card.
To me, this means that the card is legal at this point. It is official, coming from WotC, and information on the card has been officially acknowledged in DCI related material (ie, the Errata).
Am I missing something here????