I kinda wish WotC would just let him officially create a full-fledged mini-settting book for the area between Baldur's Gate and the Cloud Peaks, sort of a detailed, medium-sized adventuring sandbox for DMs and players to play in. It's just the right size without being too big, and has a lot of variety; with a big city, a depository of knowledge, some medium to small towns, a couple of temples and a fairly powerful wizard, plenty of ruins and mines, untamed wilderness areas, with the sea, forests, mountains, and so on. It's one of the reasons the original BG game was a success, due to it being a fun area to just wander around in. He is obviously very familiar with the area and could definitely do it justice...
I'm sure fits would be thrown in some quarters about "the Sword Coast Again!", but honestly, 5e doesn't have this sort of book at the moment.