Henadic Theologian
Legend
I think both approaches are valid. I think for newer DMs, who aren't sitting on a backlog of old FR books, a tight focus on an area is more useful at the table.
But if Eberron can get a big overview, Faerun can as well. (I would ignore the non-Western areas at the edge of the map, as all need between a modest and an overwhelming amount of work to be brought up to contemporary standards.)
You mean Kara Tur and Zakhara? Like I said it's likely to be Faerun focused for space issues.