In DA2, during the second act, it is said by the leader of the Grey Wardens that there are "pressing matters" to which the order must attend.
As we all know, whatever calls the attention of the wardens is always something earth-shattering, with the capability to define the fate of Thedas.
Therefore, these pressing matters must be a prelude to events to be shown in DA3:Inquisition and which certainly will figure largely on the upcoming game.
The second fact, which will be ominously present, is Morrigan's fate, her findings about the future -which she only hints at in Witch's Hunt- and her child, the purified Old God.
Flemmeth raised her with this one and exclusive mission: to give birth to an untainted dragon.
(And as everyone must have noticed by now, Morrigan's yellow eyes hunts at her being a dragon is anthropomorphic shape herself, just like her mother. Or Flemmeth could have bound the spirit of a dragon when she was young and transformed into one over time, who knows?)
If Morrigan has indeed given birth to an untainted Old God, this will concern the Wardens. They will want to protect the dragon from the taint, lest he will become a new archdemon.
Unless the child can maintain an anthropomorphic shape himself, taught perhaps by his mother.
The third fact are the blood mages' revolts in Kirwall, all spurred by "an outside group", according to Sister Nightingale, a.k.a. Leliana. Anders' act of terrorism could be linked to that. Maybe there was an infiltrator of these outside groups in the Mage Underground who convinced him to do it.
(And it would fit with Anders' behaviour. Since the beginning of DA2, he repeats he cannot have an affair with you because he willingly bonded with Justice to serve the mage's cause. He knows his life is forfeit, so he sees himself as a suitable candidate for a suicidal act.)
With that in mind, we also know through Leliana that "Divine Justinia takes the situation in Kirkwall very seriously" and through Alistair, we learn that "Orlais wants to reclaim their lost province." After the game ends, we learn that the mage situation is out of control.
We also hear Fenris comment Tevinter could be leading the outside group, but Leliana immediately dismisses the hypothesis, claiming "there's no proof of that".
Therefore, the mage problem is associated with attempts from either Tevinter or Orlais to destabilize Ferelden, that is, destabilize Alistair's rule and place a sovereign on the throne who will bend to the interests of one of these nations. Alistair may end up hunting mages down or anyone associated to them, believing they are trying to raise an insurrection and threaten his kingdom.
The Seekers may very well be acting under his orders to do so: investigate mages and former templars, hunt down the insurgents responsible for stirring trouble and discover the root of these movements.
Another intriguing fact is how people pointed out for the apparent war Seekers x Wardens. If the Wardens are protecting a dragon (Morrigan's child), no doubt Alistair would see that as a threat to Thedas: the possible coming of a new Blight.
And we see in the trailer how the sky was torn asunder by a green magic and demons came from it, including a dragon (which was not tainted, as those who watched closely must have noticed). This is another display of the mages' power, maybe the ones being agitated by the foreign insurgents that the Seekers hunt.
After that display, Alistair might feel compelled to do something about it to avoid the Free Marches becoming a magocracy, just like Tevinter is, and realize Ferelden has to, beyond hunt down mages, bring down that dragon (possibly Morrigan's child or not) and go to war with Tevinter.
(The reason for killing the dragon lies in Thedas' own history: it was the belief in the Old Gods that led Tevinter mages to go out of control and not only enslave the elves, but also try to find the Maker's place, resulting in the First Blight and the first Archdemon. Alistair might fear the uncontrolled mages seek the purified newborn Old God to repeat history, thus gaining power to implement a magocracy in Ferelden).
And what about Orlais? Well, maybe Orlais wnats to reconquer Ferelden because, as a grand nation, it has already realized Tevinter influence is spreading throughout the country and they have to stop it before they have a second Tevinter right under their nose.
(Remeber the letters traded by King Cailan and the Empress from Orlais? It's in the DA origins DLC, Return to Ostagar. Maybe the empress was trying to unify both countries in order to avoid a future war and maybe ensure protection against Tevinter influence.).
The fourth fact is the Qunari threat. The Qunari almost took power in Kirkwall. During a conversation with Fenris in Act 3, we learn that the Qunari are building their strengh to invade Tevinter and bring down the empire, a plan that is going well. He says even the Archon (A Tevinter important politician) failed to get support from other nations to protect the country in case there was a Qunari invasion.
It may also be possible that they won't stop in Tevinter and will invade either Orlais or Ferelden. Remember, they believe it is their mission to bring their truth to other "weak people". They are expansionists, and it's in that sense that they might appear in DA 3.
Taking that into account, the armies of both Ferelden and Orlais might have to join forces to kick either the Tevinter (if they win against the Qunari) or the Qunari out of the Free Marches.
It is also safe to suppose the elves would tend to favour the Qunari, since they see it as a way to break free from human oppression (remember, the elves helped the Qunari attack Kirkawall in DA2, act 2).
Finally, as to what the 'pressing matters' really are, we can speculate it MAY have something to do with either of these factors.These are all speculations from a fan and they don't cover every loose ends left by the 2 previous games, but four of the most important ones. But whatever they are, they will lead us to the center of the events that will shape Thedas's future on DA 3.