Other advantages of the Inner Sea is that Thay is there and I think they want to make Thay an even bigger antigonist going forward. Other major villains in the area are Warlock Knights of Vaasa, Queen of the Succubi Malnchanet, Unther, etc...
And it's set up to do a much greater variety of adventures. Myth Nentar for visiting an underwater city you don't need a spell to visit, empires related to Earth empires, megadungeon the Celestial Nadir, old school kingdoms Cormyr, Impiltur, Damara, Rasheman, you got the Old Empires Region for ancient empires and Dragonborn nation of Tymanther, Pirate Islands, racial divirsity (Turmish, Nathlan), city states like Westgate, you got that nation that Raven bluff is apart of, etc..., you got tell more kinds of stories there ones that involve bigger nations and are closer to big villain nations.
I love Baldur's Gate and Waterdeep and Neverwinter, but the Inner Sea region is just far richer in possibilities.