I think the big reason for many people feeling this same way about DA:I was the game becoming open world. At least for me, that's what does it to give me that 'everything is empty/dead' feeling. It is why I did not care for Skyrim, and that game is the only RPG I have played that I never finished and quit half-way through.
Open World in of itself generally isn't a problem. Quite a lot of people enjoyed Skyrim and its open world. Elden Ring is also popular with its open world. Not to mention Breath of the Wild/Tears of the Kingdom.
It's what you do with the open world that matters. In DAI the world is just scattered with a handful of repetitive tasks. With any towns being scarecely interactable (With only like 2-3 people you can properly talk to in order to pick up one of the aforementioned repetitive tasks) which leads to it feeling empty.
Skyrim had a similar problem with its overuse of generic Draugr Tombs. Though it tended to have enough unique dungeons and side quests to keep people occupied (As well as mod support so people could easily add their own content and make a plethora of changes to skills to improve replayability which is how I managed to stay engaged through 29 separate 100% completions of the game)
It's the typical "Ubisoft Syndrome" where an open world is created, but cannot be filled properly, so developers just resort to copy/pasting the same 5 activites over and over and hope people don't get bored (Which is starting to wear thin for Ubisoft themselves, with recent Assassin's Creed and Far Cry games getting less positive reviews as people are tired of this formula). Which not only creates tedium but also makes a world feel dead because unique places aren't unique, since you just go over and do the same thing you've done 100 times before.
