My thoughts on DA2, especially after the demo, would seem to have the main conflict in the sequel to be a split focus between the collapse of Chantry rule and a renewed Qanari threat. If that's the case, and we see the resolution of the latter in this game, then the third could very well be a focus on the looming war with the Tevinter Imperium, and possibly the redemption of the Dark/Light City. If you read the wiki, the only reason why Tevinter doesn't flat out attack Fereldon is because it's caught in a near-constant war with the Qanari. If this threat is removed in this game, then it'd only seem too likely that the third in the series would see their expansion. Also, Tevinter is at the heart of it all: blood magic, the elven diaspora, the darkspawn threat, and the corruption of the Old Gods and the Golden City. Seems to me like the perfect endcap in the series, and the direction of this game would certainly steer the player and storyline towards that!