If I read it correctly, through my non-lawyer eyes, the case was tossed because the plaintiffs lacked legal standing to bring the suit (whatever that means), and the SC actually refused to hear it without comment.
I still think a stronger lawsuit would work. But, as I said, I'm not a lawyer.
I'm sorry, a stronger case won't cut it. The plaintifs lacked standing because the issue was between the congress and the president. The congress and the president were in agreeement, so there was no issue to resolve.
In the present situation it is the same. The congress, with a 2/3 majority approved the measure and it has become law. In order to have a standing before the court, the injured party (in the case Congress itself) must bring the case against the president [assuming the president had "declared" war thereby usurping congress perogative.)
But again, the Constitution is silent on the methods of declaring war and the appeals court is sticking it's oversized nose in where it doesn't belong. With hostilities days away, the court should just STHU.