1. Dual characters would be interesting, especially if let’s one is a Qunari that wants to conquer Tevinter and fight Solas, and the other is an Tevinter ally(maybe even the Inq) and wants to save the wold from Qunification and Solas.
At one point, preferably towards the end, these two actually meet, and you get the option to continue the fight with only one of them, in which case the other dies and everything you accomplished as that char goes to waste.
2. Or one char with a twist. But this would be more difficult to implement, because it will not allow you to import your Inq, it will be only a world build with choices, mage-templar, have the GW joined the Inq or they were kicked out, etc. This world build will conveniently forget the race of the Inq.
You get to play half the game as a Qunari(the race doesn’t matter), fight the Imperium and their allies, Inquisition forces included. At one point you face off the Inq’s romantic interest, you fight and kill him/her. With his’her last words, she tells you she still loves you Inq.
The shock of it makes you break free of the mind control and you realize you are actually the Inq, were captured by the Qunari and they played with your mind using the awesome powers of Qamek.
You are then faced with a choice: get back to your former allies and try to rectify some of the things you did while brainwashed, or realise the Qun is the true way and continue with your mission. Imagine having to fight/kill every one of your former friends.
I know the implementation of such a concept can be tough if not impossible, and the KOTOR already used this with the Revan revelation, but honestly, every good idea has already been used before in other franchises, so there isn’t much room for novelty.
Even a cliché setting can be interesting if properly implemented.