What are eras anyways? What's the benefit for them?
Does each era have a distinct military system logic - but then the tech tree is fluid and you can push forward and get a unique type that can rule the battlefield completely.
Is it for governments? Or wonders? Or Golden Age points? Is it mostly visual? The aesthetics? Humankind had them separated by a change of cultures, but that wasn't liked. If civ 7 has some sort of leader change mechanic (and I hope for that), it should be independent of the eras and instead be based on gameplay needs.
But yeah, what do we need eras for? I'd rather propose to think of certain breaking points that change the rules of the game. Things like Nuclear, Flight, Industrialisation, Deep-Sea Travel, Gunpowder, Horse Archers, Monotheism, Bronze, Agriculture and so on. These "Star Technologies" represent a break - a before and after - and I'd define the eras in these terms.
Tribal - Bronze - Classical - Imperial / Medieval - Early Modern / Colonial - Industrial - Modern - Information - Future does feel like it makes sense though. I especially like Tribal - Bronze in that it implies a pre-game before settling down