Interesting thoughts on this. It reminds me a lot of what the Warden goes through in DAO and in Awakening (and in DA2, a "save the Vigil" Warden is canonically given a blistering deposition IIRC, and Alistair mentions the First Warden was "not happy" about the political games the HOF had to play), not to mention the ire the Wardens endure in Inquisition. Heroes never get any thanks in Thedas, and nothing ever stays stable 
The First Warden was the one who let the HOF run Amaranthine in the first place to set a precedent for post-blight relevance for Wardens and the HOF did pretty well. Also, I don't recall having the leaders of the free world put the HOF on trial for saving the world.
Or even Hawke for that matter.
I have a feeling that the Inquisitor is being scapegoated as an excuse to get rid of the Inquisition as a threat to the status quo.
I really hope that this dlc doesn't railroad us into losing...this is a great chance for the melting pot to really get stirred. Like have the Inquisition leaders decide to declare that they are beholden to no one and either withdraw all of their resources and connections from the ungrateful Orlais and Ferelden and see how they fare then or aggressively monopolize them and laugh when your enemies unsuccessfully fail to counter you.
As for the Qunari invasion and Solas? Not sure if there's a connection just yet.