She should have sent Jace or herself to bait Aemond. Then had the unknown dragons hiding waiting for Aemonds to take the bait. Which in that case he would have, then descended on Vhagar with Seasmoke,Vermithor, Silverwing, Syrax and whatever Jaces dragons name is. It wouldn't have been a fight it would have been 10 seconds of Vhagar getting ripped to pieces.