I sit back and read all of these posts and just smile. The fact that we've got people in here spending time attacking or defending a DAI companion just goes right back to my OP - there are some really well written characters in DAI because they elicit discussions just like this.
So, in the spirit of things, I'll lay out my opinions about my Advisors and Companions. Feel free to disagree with me - that's part of the fun of it all!
Leliana - Doesn't hold a lot of interest for me. Wasn't crazy about her in DAO, was confused by her cameo in DA2 (though now I understand it), and she doesn't quite fit Varric's description of what makes a good spymaster so I guess you could say she still confuses me. However, I am vested enough to dislike her during In Hushed Whispers so perhaps I'd enjoy a darker Leliana? Not sure.
Josie - Like her but there's no big attraction to her. She's the weakest of the 3 advisors but I also realize part of that is because she's new to us whereas the others are not.
Cullen - I have deep respect for him and would still have that even if he weren't romanceable and therefore wasn't my LI 90% of the time. I regret the contradiction presented in the epilogue slides of DAO vs the reality of DA2 but then so does Gaider. As he said, they learned the hard way not to write themselves into a box like that. But, even though I'm not a huge fan of DA2, I really like how they took his "A-HA!" moment when he realizes Meredith isn't in the right and used that as the groundwork for his joining the Inquisition. Could his story be better? Oh sure. But I understand the confines of a game and the resources available and like what they did with him and his dealing with his Lyrium addiction.
Cassandra - "Pretend you don't know this about me." -- it's lines like these that endear me to her. As a woman, I love how well rounded she is. We're complicated creatures and she conveys that complication quite well. In RL, I'm in upper management and as such, I spend my day looking at the big picture, making tough decisions, and juggling a multitude of details. But when it's over, I want to get swept off my feet by Cullen, or chatter like a schoolgirl to my husband, or go kill some monsters in an MMO Raid. Somedays I know exactly what must be done and how to accomplish it and other days I find myself floundering and very thankful for the friends and family I have around me to help me find my way. Cassandra portrays all of these things that make strong women strong and she does it beautifully, imho.
Blackwall - I feel betrayed by him. Every time. Even though I usually pardon him (and I always recruit him) he angers me because he tells me he's 100% committed to our cause but not enough to come clean when we need it most during the Warden investigation. Yeah, it wouldn't change anything but I do not like to be led on and that's what I feel he does to me up until Revelation.
Iron Bull - Used to be indifferent but since I saw his betrayal in Trespasser, that's grown into dislike. All the "I won't do anything to jeopardize the Inquisition" is BS and I do not like being lied to.
Varric - Love him for a kind of odd reason. I imagine him as Gaider due to the whole writing thing and I have a huge affinity for him because I'm an amateur writer and can really relate to some of the things he says about writing. In DAI, that love grows when his walls come down a bit and he lets you help him with his grief over Hawke.
Sera - I wonder what really goes on in her head, but it doesn't keep me up at night. I'm rather indifferent to her like I was indifferent to Merrill. Not sure any amount of "better" writing would change that though - I just don't find people like her interesting.
Cole - Like him but he doesn't fit in DAI for me. I love trying to make sense of what he says but I'm not crazy about his place in this story.
Dorian - Love him as a friend, bored me to tears as a LI. Apparently I prefer M/M relationships when they're identical to M/F ones since the ONLY thing that kept me coming back to DA2 was my male Hawke and Fenris relationship. But as a friend, Dorian is wonderful and I'm always disappointed when he runs out of things to say to me!
Vivienne - Hate her. Used to just not care about her but when she stole the Divine's seat out from under Cassandra in a recent playthrough, that turned to true hate. Now, every word she says feels like nails on a Chalkboard. So yes, she's very well written. 
Solas - Hate him. Didn't like him much before Trespasser but it migrated to hate when again, I realized his whole life was a lie. Interestingly, this makes the camp scene between Haven and Skyhold even more moving for me. That song was my hook into DAI but now I get that song and then the face of my betrayer and it just cuts to the bone. He's the reason we're in those freaking mountains and why I have this stupid mark that is going to kill me some day and when I look at him in that scene, I truly break down and cry. So, hats off to Gaider on that one for taking the most moving scene in the game for me and making it even more potent once I learned Solas's true agenda.