Expand the melee weapon selection with additional knives, axes, and other realistic melee tools. New weapons could offer different animations and handling while remaining balanced against firearms.
I think this could be cool if they weren't just cosmetic but had different uses, like the sledgehammer in BF6, or entirely replaced by a gadget or something but I think that nobody would use melee at that point. Maybe you can take an extra grenade instead of melee? Something of the sort. But if new melees would be introduced all with different stats, everyone would just use 1 because it's meta.
Tactical axe would be cool, plus you can also throw it as a tomahawk.