Once you start building a team and getting all the companion dialogs it definitely has that ME2 feel...

Also in terms of culture, I'm really impressed with the side quests. Especially since I barely did any of them before completing the main story, and I'm just going around the map working through side quests now - they really focused on the culture of the tribes to a point that they feel real and diverse, and not made up stereotypes. For example you'll see certain characteristics of a tribe, but then do a sidequest with a clan in that tribe or an individual person that completely shifts that characteristic, to the point that they'll talk about struggling with that internally.

Also just yesterday I did the series of side quests dealing with Eclipse holdouts - I had no idea they were even in the game.