I think it won't happen because even in the core fandom there seem to be roughly as many people saying no as there are saying yes. DLC targets fandoms more than full game releases do: developers know they're the players who are far more likely to dig out a several-month-old game and say, "yeah, absolutely, I'll spend another $5-$15 on it." The myriad purchasers (ideally) who bought the game on a more casual note? Some have already sold it, even. They beat it already. Why would they go back to it? "Fans are weird."
It's why there's so much delicious fan service in certain Mass Effect DLCs. Lots of lovely winking. BioWare wants everyone to buy the DLC, and will take advantage of telemetry to try to find a sweet spot of sorts, but end of the day, they know what we know: we're the folks who are the most likely to pop that disc back in, cough up extra cash, and set out from the war table bound for new destinations.
I just don't see Kirkwall getting enough fans hyped to justify the cost assessment given DA2's lasting legacy. Unless they throw caution to the wind and market it perfectly. Then maybe it'd work, but I dunno that they wouldn't just focus on DLC ideas that are more guaranteed to be alluring.
A before-and-after video between engines and a lampshading DLC title such as "Most Exalted: Kirkwall As It Should Be" might drum up the tumblr engines enough to do alright. With any luck DAI's apparent good reception will lead to enough players new to the franchise being interested in it as well -- they can just say, "oh, I heard a lot of people didn't really like that city but it looks sweet to me!"