"You keep saying that word. I do not think it means what you think it means."
As terrible as I, too, think this decision was, it was a decision by a trial court judge. "Precedents" don't attach to trial court decisions, only to appellate court decisions.
If Restis appeals, and the dismissal is upheld by the appellate courts, then there will be a precedent, with everything that implies. Similarly, if he appeals and the dismissal is reversed, a much more favorable (to your and my tastes, anyway) precedent will attach, which can be used to argue against any other attempts to toss suits to which the government isn't even a party on the basis of the State Secrets Privilege.
For the moment, however, this is an "isolated" incident, and can't be used precedentially in any similar cases.
EDIT: Yes, follow-ups, there are other definitions of the word "precedent". In the discussion of a legal decision, however, the legal definition takes ... well, precedence.