While I love Dragon Age: Inquisition and it marked the beginning of the end of one of the hardest times of my life, I agree that it has flaws and I am very interested to see the next installment goes. Wherever it goes, however, I am not so terribly worried.
I know that Dragon Age: Inquisition was not to your enjoyment but I genuinely hope you'll find something to like, maybe even love, in the next installment. Who knows, we might even find ourselves agreeing on a lot more things in the future 
I was so hyped for DAI. I went back and read all the books leading up to it, replayed DAO and DA2 TWICE to have some world states to import as well as pre-ordering the Inquisitor's Edition.
I think what really did it for me was the lack of cutscenes. Prior to launch (going off of the leaked PAX demo) I assumed that the "zoomed out" conversation camera angle would be only used for non essential NPCs such as vendors and such. Then when the E3 2014 demo came and we saw that elf lady give the quest regarding her dead husband and his wedding ring, I again saw that zoomed out camera and started to get worried. My fears came true when I bought the game and found out that a majority of the conversations in the game did not have cinematics to them like in DA2 and Mass Effect. Even many conversations with companions in Skyhold/Haven did not support cutscenes. This really disconnected me from the experience to the point where I could hardly see the emotion of my Inquisitor. Furthermore, this was only compounded with the monotone style of personality that the Inquisitor had which was different from Hawke and even Shepard.
This picture really sums up my opinion about the dull personality of the Inquisitor. Just replace Tim Duncan's face with the IQ.

Then what got me again was that I found out that there was no main story content in many of the locations like the Dales, Exhausted Plains etc. They were just there for XP farming and item crafting farming and nothing else and nothing more.
Then there was the villain which we all know that some people loved, but many others hated. Loghain in DAO and Meredith and DA2 had more "umph" to them than Corphy. After having Loghain and Meredith, both with complex villain traits (kill 100 innocent people now to save 1000 tomorrow style approach) as opposed to the generic Sunday morning cartoon style of "I want to rule the world!!!! lolololololz" style villian of Corphy. Bioware is better than this.....
So yeah, I am glad that many enjoyed and I am glad that it was a financial success for them. But I am also glad to know that DA4 will not be like DAI and should represent what Bioware really originally intended to do for a next gen Dragon Age title.