Ideas/Feedback for New Campaign
At the risk of being a stick in the mud I'll take this time to argue Eberron's themes and style is much more than just magepunk and trains. Feel free to ignore, I'm simply trying to help but identifying the other things which a world borrowing from Eberron might need
-The setting is much less about what you are than where you're from. The average person doesn't care that you are a non-human (so long as you're not a goblin, warforged, shifter or changeling), they care that you're from the country they fought against in the war. Dwarves and elves, orcs and gnomes all live together fruitfully (if convinced their race is generally the best one). Half-orcs and half-elves, rather than be outsiders to their parent races, are key and important parts of their cultures. The Khorovar are a race of people who only came about because the elves and humans came to Khorvaire, and the half-orcs are a symbol of the cooperation and unity that the orcs and humans of the Shadow Marches have achieved (despite constant feuds that'd make a Scotsman blush)
-Good is weak, evil is fractured. The great heroes of the world are gone, the powers that can affect things are either locked in one place (The Keeper of the Silver Flame can't leave the city of Flamekeep without losing her cleric levels until she returns, the great druid Oalian is an immobile pine tree) or are not benevolent (though fighting for the good of the world, the dragons of the Chamber start wars, assassinate people and often let evil win in the short term, and are not above simply killing everyone involved and starting over). Arrayed against them are a half-dozen evil factions of note (and many smaller ones besides) who are at cross purposes to each other. The Lords of Dust want an apocalypse (but work against each other almost as much as the Chamber works against them all, so only their own demon overlord may rise), the Dreaming Dark wants peace and dominance in order to escape oblivion, the daelkyr simply do not care that their art warps the very nature of those they touch, and the more mortal groups like the Aurum or Emerald Claw are interested in material gains, money and martial victory, while their leaders could be controlled by the big guys above.
-There are no absolutes (except immortals). Immortal creatures play out long games and stories among themselves, the planes and the fiends act according to their nature. But everything else CAN be good, evil, lawful or chaotic as its personality suggests. Clerics of the Silver Flame can be corrupt, or zealous, or they can be honest self-reflective people. A monster can believe in honour in battle, in dignity of its foes.
-The world needs heroes. You, the party, are the important people. There is no grand detailed timeline saying this happened then this happened, what serves your story is what happened. You will have the power to change the world, you will have the power to overturn wrongs and forge a brighter path.
Side note but also something I love is that every non-human race is obsessed with history. The dwarves don't care about facts, they care about what makes a good story. The elves are determined that any elf who dies be remembered in some way (different factions have different practices), the gnomes are fastidious record keepers to the point that they spread organized religion, science and trade long before humans. The halflings and the shifters each have a powerful and lively oral history, the orcs believe in the tradition of the old ways and in doing whatever you do with all your passion. The goblins literally once ruled the continent and their works built the foundations of the modern cities. The changelings pass down jobs and titles alongside the faces of those people, the town healer in a changeling village will look like the same person for decades even though generations have been this one role.