I actually like how DAI leaves it up to you to define your own motivation. It's hard to remember now, but early games were very much like this. Nobody forced you to go to a certain area; nobody forced you to go into a dungeon.
That is a unique take on the matter that I have never heard before. Can you elaborate on why you think you coming up with your own motivation is better?
Here is my beef with it; using that logic, I can play games like Dynasty Warriors / Pirate Warriors (which is a series of games that basically consists of nothing but endless horde mode) and still label it an RPG because I can contrive a motive, no matter how weak, because of my actions (i.e. "I'm killing these guys because they stole my cheeseburger 10 years ago" despite there being no in-game indication of this). In my opinion, a good RPG needs to give you purpose to what you are doing and consistently reinforce it, otherwise it feels no different to any other genre. And that purpose is usually given via human interactions, which are few and far between in this game. Even when they do exist here, I felt they were lack luster.
Quests that I felt hit a perfect balance of combat / dialogue are Cassandra's and Varric's companion quests. Iron Bull's companion quest was also comparable, albeit much shorter. Unfortunately, many quests fail to hit that balance of dialogue / motive and combat (and to an extent, exploration), thus leading to a situation where you feel like you are playing an arena fighter rather than an RPG.
I haven't played as many RPGs as most people; all I've played is the ME trilogy, DA trilogy, Fallout 3, Fallout NV, Oblivion, and Skyrim so I don't really have any RPG knowledge whatsoever prior to 2006. Unless you want to count the original Pokemon games from the 90s, which would technically qualify . . .
Let's not get into the whole "how to define an RPG" thing.
It's obviously subjective criteria, but it seems a large portion of the posters here in your thread seem to share this sentiment.
What I'm sayng is that if a game that dubs itself an RPG yet has no dialogue or interaction with NPCs, most people will not consider it an RPG. Most people would likely label it an "arena fighter" and rightfully so, because the biggest factor that differentiates an "arena fighter" and an RPG is dialogue and interactions. You pound on waves of enemies in both types of games, but the RPG actually gives you purpose and consistently motivates you to do so. Without that motivating factor, the RPG loses a lot of what makes it an RPG in many people's eyes.