So, to answer your question: If the setting were at the time of From the Ashes, it's a world at war. Or, more specifically, coming out of a war, and preparing for what will certainly be the Last War. Leaning heavily into that, that would be a vibe that is not in the FR.
Good is on the ropes, but Evil is fractured as well (in that no alliances are possible). Lots of questions remain about who will side with whom, or at least what can be done to secure those alliances. It's big stakes, but the PCs are front and center, with no Harpers or Elminster around (there's the Circle of Eight, but they obviously can't be trusted).
The bleakness, the fiends as troops for evil overlords, the mysteries that are tied into the salvation of good people if they can be solved...basically the last chapter of Ivid the Undying...that all feels pretty unique to me in a way I can't exactly recreate in another setting.