Destiny 2 has had an ebb and flow when it comes to the drop rates of exotics, from the launch of the game when exotics were handed out left and right, to Destiny 2's Forsaken expansion when exotic drops became extremely rare. Currently in the game, now near the end of Year 2, exotics have been a bit easier to come by with Xur selling many of them and drop rates being made a bit more generous. Shadowkeep is going to make another change to exotics, providing a clear path for players to earn them and potentially farm them. But it does not look to be an easy path.
The key is how Shadowkeep is retooling the Nightfall by adding additional difficulty modes in a version of the Nightfall called The Ordeal. The higher players go up the difficulty ladder, the more likely they are to get exotic drops. The new difficulty modes, from easiest to hardest, are Adept, Hero, Legend, and Master. In new gameplay of Shadowkeep shown in a new ViDoc about the game and its future, the difficulty selection screen for the Nightfall is shown, which identifies exotic drops to be "Common" in Legend and Master difficulties, which are 950 and 980 Power, respectively.
While the screens for Adept and Hero aren't shown, from comments from the game's developers, exotics are still a possible drop in the easier difficulties but rarer. In addition to the straight Power difficulty, each step up difficulty also adds more modifiers to the Nightfall to make it even harder.
To complete these harder Nightfalls in Shadowkeep, players will need to start by leveling up to the new level cap of 950 which is the cap for Powerful gear drops. Then, players can get to 960 by completing pinnacle activities like the Garden of Salvation raid and receiving drops from that. After 960, players will rely on the Seasonal Artifact to give them a Power bonus one point at a time.
There is no true level cap in Shadowkeep because there is no limit to how high players can level up the Seasonal Artifact, which is based solely on XP points, so it's likely that some players will soar well past the 980 level of the Master difficulty Nightfall.
Destiny 2: Shadowkeep releases October 1, 2019 for PC, PS4, and Xbox One, with a Stadia version also in development.