In an interview at Gamescom regarding Destiny 2, there are details about the core element, the Strikes.
In the interview with Gamesradar, Justin Truman talks about the role of Strikes in Destiny 2:
- the Strikes are meant to tell a self-contained story
- this story revolves around an interesting character, usually the villain of the Strike
- around this story, Bungie builds the best possible combat experience that can be replayed repeatedly
Truman says Bungie now has a clear division of the individual PvE activities. In the campaign, the focus is on spectacle and story. In the Strikes, the focus is on finding the best combat scenarios and chaining them together.
The Strikes are designed so that players want to repeat them 20, 30, or 40 times over the years.

Destiny 2 – This time we know what we are doing
Mein MMO says: People always ask what the “main difference” is between Destiny 1 and Destiny 2. Statements like this one regarding the Strikes indicate that the main difference is: “Bungie now knows exactly what works and what doesn’t.”