Bioware has massive opportunity in the single-player fantasy RPG market.

I feel that the ending of Trespasser leads to the Inquisitor having to be the protagonist in the next one. But I know they probably won't because of that idiotic "new protagonist every game" nonsense. 
The Inquisitor being a NPC is worse than them not showing up at all in my opinion. Bioware has ruined every single of the protagonists they have done that with. The ruined my Revan. They ruined my Hawke. I do not want them to ruin my Inquisitor too. They were my favorite protagonist. 

I'm glad they managed to capture yours well. They didn't with mine, with pretty much every aspect of them going against how my Hawke was. 

Well, the main thing was their opinion of blood mages in DAI, calling them all monsters and stuff like that. Despite, you know, my Hawke being in a relationship with a blood mage. Then there were things like their views on Wardens, the relationship with Varric, etc. The Envy Demon did a better job capturing my Inquisitor than Bioware did Hawke, and that's a very low bar to not be able to get over. 

Legacy Cory was a bit scarier iirc. Regardless Inquisition Cory is a limp fish flopping around on a boat deck!

A big part of the reason why I want DA4 to turn out not to be about Solas at all is to see the reactions. So many people assume he'll be the antagonist of the next game, including certain gaming news websites, who I've seen make this claim despite having nothing whatever to back it up.

They spent all of Inquisition and all of Trespasser setting up Solas as the main antagonist for DA4.

I believe I have stated but it is worth mentioning again: I would almost them rather that Solas be A bad guy in DA 4, even the Big Bad of DA 4, but we almost rarely ever see him throughout the course of the game. Granted I am torn because, much like with Cory, I think there is wonderful potential for a deep personal narrative with Solas and whoever the protagonist of DA 4 ends up being, (Yes Hanako this also includes the Inquisitor).

But the advantage of making most of the game deal with the Qunari or Imperium politics is it gives Solas a backdrop against these actions. I have been considering (not for the first time) that BioWare has a magnificent opprotunity to learn from their mistakes with ME 3. Solas is Overpowered as all hell and they could just give us some mcguffin to stop him or they could give us the ability to at least try and talk him down. Make the Solas part the grand oversweeping narrative of the game, the high level stuff, the struggle between your protagonist and the qunari can be the low level knitty gritty personal story that really drives the game.

Well, first, notably, because they hopefully understand that power/threat creep does not a good ongoing story make.
And second, because they pulled the whole "political conflict concerning modern-Thedas factions is a smoke screen for destroying the world" in Inquisiton, why just do the same story again?

Personally, my money's on something Titan-related. As world-changing revelations go, "ancient assholes came back to life" is way more common and way LESS interesting than "the earth is made of giants and magic comes from their blood".