I think party banter is probably my absolute favorite thing about Bioware games.
Elevator convos were great. Heck, the banter between a romanced Tali and your squadmate when you first go on a mission with her in ME3 is probably one of my favorite moments in that game.
But if they're going open world like they did in DAI, for the love of god they need to realize that they have to increase the amount of party banter. There was as much banter recorded for DAI as there was for DA2 and DAO, but no one thought "hey, we're padding the game's play length with hours of running around the wilderness, maybe we need them to talk more." So people got long stretches of silence (the banter bug didn't help).
I also really like when characters don't like each other all that much, and squabble with each other. Having Aveline and Isabela together in DA2 is pure gold. And listening to Morrigan and Alistair argue, or listening to Morrigan and Leliana get catty with each other if you've romanced both of them is fantastic immersion.
Even more than banter, though, I'd like to see them go back to a DAO style where the companions with you argue and bicker when you need to make big decisions. If they can't have as much banter with squadmates because of combat, at least have them say unique things at the climactic decisions within major quests. It adds flavor and replayability.