Cassandra is my Divine of choice as well. Was pleased that she got the spot in my first run, plan to keep it that way on my other ones too.
I do not have an ‘ideal’ Divine, because I would rather not pick one. What I would do (right after defeating old Cory) is write a decree, telling those who have served the Inquisition loyally, that they have fought long and hard sacrificing limb, and life, so that Thedas can have a tomorrow. I would tell them that I would liquidate all of the Inquisition’s assets so that they can rebuild their homes, and honor the fallen. These assets would be used to help them resituate into their lives--if they only agree to it. If not, they can continue to serve the Inquisition, but most likely as tools of the chantry. However, any Divine who does not give the people of the Inquisition the respect to choose whether they want to remain, or leave and live their lives, is a despot not worthy of her position. Either way, I would have my Inquisitor ask them to show him the same respect, of said choice (to stay or leave), and then my Inquisitor would quit and ride off into the sunset.
A nice but risky gambit, for someone who wants to say “**** you” to the chantry, and not be its tool. My Inquisitor was there to stop Cory, and the rifts, not to become the chantry’s militaristic pet. Too bad it's not an ending, I'll just hope for a mod. lol