When a new Mass Effect game was announced by BioWare, fans rejoiced at the reveal of new content. From the short trailers and few other details fans have gathered so far, it seems that Mass Effect 4 will return players to the Milky Way Galaxy, where Shepard's war against the Reapers began and ended. Also, in the reveal of Mass Effect 4, fans got a look at Liara, one of the companions from the original trilogy, who appears to be significantly older than when players first interact with her.
Details like Liara's age and some of the teaser images for Mass Effect 4 have raised plenty of questions among the franchise's fan base. Some hopeful people are wondering whether there's a possibility of Shepard returning in Mass Effect 4, while others are questioning whether BioWare will canonize a specific ending from Mass Effect 3. Most, though, are happy to see a return to the sci-fi setting, especially with a return to where the first games began.
However, even with a potential return to the Milky Way galaxy in Mass Effect 4, it seems that gameplay may reflect the open-world style of Mass Effect: Andromeda. This is according to a recent job listing at BioWare for a Level Design Director. A requirement for this role is to have experience in "nonlinear, self-directed level design." This heavily implies that the new Mass Effect game will let the player choose their own path around a level, rather than have that choice laid out for them.
While this doesn't exactly mean that the next Mass Effect game will be open world, it does imply that the game will take more influence from Mass Effect: Andromeda than it will the original trilogy. Mass Effect 1, 2, and 3 all used a more linear style of level design, directing players on a given path without many options for taking different routes. This decision for a less linear style of levels could still restrict Mass Effect 4's main story to select levels, each with a multitude of paths to take, similar to the level design of the Dishonored games.
If Mass Effect 4 is ditching the old level design in favor of an approach similar to Mass Effect: Andromeda, it is possible that other features from the spin-off game could feature in the new title as well. However, it does seem that Mass Effect 4 will be taking a new direction in a lot of ways, and some even believe that it must make up for some of Andromeda's shortcomings by introducing new alien races and companions.
Mass Effect 4 is in development.