I was never a fan of Elite Classes in BF1 because you didn't earn them, you got them for losing. It would be great to see them comeback as unlockable elite classes. Flamer thrower and tank hunter would be especially cool classics.
Maybe even a mortar-based class because that was a bit OP in bF1.
Maybe a trench raider that has both medical and ammo crates, insta builds or builds reinforced structures.