I believe "A Path of Daggers" may mean three separate things:"

1) Mat and the Seanchan-- The primary focus of this book will Mat and his dealings with the Seanchan, who will find him in the ruins of Ebou Dar and take him aboard their one of their ships (or perhaps to an island...maybe Tremalking.) There he will meet this Daughter of the Nine Moons, and either Mat will help the Seanchan, (being the excellent military general he is, with the added bonus of knowing thier ancestors in his past lives) or he will get the Seanchan to back him. Thing is, Mat has to get the Seanchan behind Rand, but they're currently fighting a war, and will continue to do so for this next book as well.

2) Padan Fain-- for the last few books all Fain has done is hang around high-profile people under the guise of an advisor. These people were among Rand's most imminent threats at the time. He was there at Toman Head and did have dealings with the Seanchan. The worst he had done to Rand besides hunting him the whole series is slashing him with his dagger. (A pity he wasn't there at Shadar Logoth in aCoS.) This book, Fain will be with the Seanchan, who rule in the south and west. There will be fighting in Illian from Altara, and perhaps Perrin up in Ghealdan will be drawn into it too. But I'm getting off-course. What I'm trying to say is, Fain and his ruby-hilted dagger tie in the Seanchan.

3) Arangar and Osangar-- no one knows where the hell Osangar is but he'll probably show up in the Seanchan-Rand conflict in the south. This third point probably doesn't tie in as strongly as the first two, but it's a possibility.