A rudimentary inspection of the latest trends in the First Person Shooter genre would be rather bland, to say the least. For years, every game wanted to show you their version of World War 2, and once people grew tired of shooting Nazis in the face, the time period was all but abandoned in favor of the modern age of combat. Now that people are starting to realize that laser guided missiles and guns that can fire thousands of bullets per minute are not as exciting as they once thought, developers are scrambling to find that new time period/theme that will make their game the game that started a new trend. Battlefield tried their hand at cops and robbers, and now they are going to go back to the trenches with Battlefield 1, but the question on everyone's minds is simply "Will it be fun?"
After all, if you paid any attention in history class, then you are probably aware of how static and brutal the Western Front of World War 1 was. Charging across open fields into a flurry of bullets, being gassed to death before getting a chance to fight, and even drowning in your own trench were very real concerns that soldiers had (especially on the Western Front). Of course, this was also the age with an unprecedented wave of innovation that led to things like tanks, combat aircraft, and machine guns (or in other words, everything that makes the Battlefield series Battlefield), but the first World War simply never lent itself to good gameplay mechanics (at least in theory).
On the other hand, the fact that there were instances where soldiers dug tunnels under enemy trenches to blow them up, zeppelins, and vehicles that were vulnerable to more than just laser guided missiles could lend itself to the general Battlefield formula rather well, even if historical accuracy and realism has to be sacrificed a bit. Furthermore, not every battle took place in the trenches of the Western Front, so there could actually be a rather diverse set of maps, which in turn can lead to more interesting classes. Obviously, the usual set of classes would need tweaking, but it is entirely possible that it might actually lead to a more balanced class system than before.
For instance, Engineers in previous Battlefield games could easily be considered the most well-rounded class in the game, simply because their primary weapons were just as deadly as the weapons given to the Assault classes. However, Engineers in Battlefield 1 could conceivably only carry a pistol and an anti-tank rifle or an explosive, which would both serve the purpose of making pistols incredibly useful, and preventing the Engineer class from acting as an Assault class substitute. True, it would also mean that you can't run and gun given that automatic weapons weren't as commonplace, but at least this minimizes the chance that Battlefield 1 ends up being yet another game where all you see are Mountain Dew and Doritos fueled montages.
Plus, it's not as if modern audiences are necessarily adverse to slower paced games. Rainbow Six Siege is definitely on the slow side, and it didn't exactly sell poorly. The fact that World War 1 is relatively unexplored territory also opens up a world of possibilities for any single player content that Battlefield 1 might have, free from your generic "evil Russian/Chinese/terrorists want to take our freedom" plotlines. Even if Battlefield 1 doesn't sell well, it could set a precedent where the industry takes a step back from near future sci-fi themes. At the very least, Battlefield 1 is a solid "wait and see," thanks to its comparatively ambitious theme alone.