Larger, Living Worlds
We’re not gonna lie, some of the locations in Destiny are simply gorgeous. However, they aren’t the most lively things out there. Sure you have some enemies here and a few public events, but all in all the worlds feel relatively dead. After a little while you find yourself simply falling into a cycle of farming enemies or making your way to objective points sort of brainlessly. The worlds are very constructed.
Destiny 2 could benefit from larger, living worlds. They could be full of civilians like we saw in the trailer, as well as quest givers. Outside of hubs could be roaming, wild beasts, and enemy encampments. Maybe optional objectives that work like the public events we have now, or even complete sidequests you can stumble upon while playing solo.
Destiny was about pushing back the Darkness so that we could protect humanity, but there was no humanity to be seen throughout the game. We were just fighting on and defending dead worlds. If you really want to keep players invested, give us something worth fighting for.