opinions
But, of course, this is incredibly subjective. I think DA:I has the best cast of characters in a DA game by far.
Same here. I like how the companions are written in DAI, in some ways imo they are better done than in previous games. In DAO I only found Alistair and Morrigan to be of any notice, in DAI all companions stand out to the point where people think that there are more of them (when actually they are the same number 9).
DAO was brown and sometimes purple, it had its moment, but overall I didn't found the grittiness to be convincing enough to care. DAO has a typical fantasy fluff story with somewhat watered down plot because it's a game.
DAI has its moments too, it may be visually more sanitized (no throwing rape and such in your face) but I've found the desolation of Exalted Plains to be on the point, the Winter Palace depressing and gory, the "Game" horrifying and Envy segment creepy in a way that finally didn't remind me of B horror movie.
Both games approach things differently, I wouldn't say that one does it better than other.