We know for certain that we’ll be visiting Kashyyyk. That was shown off during the E3 gameplay footage. Beyond that? Who knows. The initial footage gave us a glimpse of a star map showing three (additional?) planets to explore, but the true extend to our ability to explore is unknown at this point.
Respawn have been very deliberate in how they’ve described Fallen Order. Repeated use of the term “Metroidvania” appear to be deliberate in an attempt to quell our expectations regarding exploration.
An emphasis on back-tracking, or exploring new areas, with new abilities, hours after you initially visited the area will likely be the focus here, however it would be nice to do so on planets that haven’t previously been focused on. Deepening our understanding of the wider Galaxy, away from planets that we’ve seen on multiple occasions, would be very welcome, and would add a feeling of uniqueness to the title.
Failing this, an entire section set on Moraband would be pretty slick.