That would be cool and another location for pirate themed could be Luskan and the 5 captins and cover some territory up their
We have had too much Swordcoast right now, I mean every adventurer has been on the Swordcoast basically except CoS and ToA and honestly doing a Luskan Pirate Campaign would basically require reusing Jarlaxle and his faction. Honestly I'd just use a lot of W: DH's materials with SCAG for Luskan.
Making it the Sea of Fallen Stars on the other hand takes us to a very different region, one very popular and desperately in need of attention. Something Pirate or Privateer Themed, but let's us explore a vast part of the realms that has been neglected in 5e. Honestly the Sea of Fallen Stars is my favourite part of FR because because it has many of the most interesting nations all connected by this sea. And it's rich is history and interactions. It's very diverse.
There is Cormyr, Sembia, Algorand, Rasheman, Thay, Mulhorand, Unther, Vesperin, Tymanther, Turmish, Chessenta, Airspur, Nathlan, Thesk, Raven's Bluff. The region was the sight of all of the biggest wars and changes during the Sundering except for the War between the Lords Alliance on the Swordcoast and North against the Orc Kingdom of Many Arrows as well and the Civil War to over throw the Djinn in Calimshan.
The biggest most wide spread war was the Shadovar/Sembia War with Cormyr/Myth Drannor/the Dales. Then the Mulhorand revolt against the Imaskari lead by their Gods. Gilgeams war to rebuild Unther, after the war he'd be fighting on Abeir with the Shyr Empire, and finally his war to destroy the two Dragonborn cities. Some major battles with Pirate fleet lead by a chosen of Umberlee.
And heavy geographic and political changes across the region. A new Queen in Cormyr. Most nations in the region rebuilding and expanding after great suffering during the Spellplague and Sundering. Gods have returned. And inside the Sea of Fallen Stars are pirate islands, Sagahuin Kingdom, Myth Nentir (an Sea Elf city who mythal allows air breathing creatures to breath water), Triton Cities, Mermaid Cities, cities of weirder sea creatures. IMO it's the coolest part of FR.
Plus it's where the great rain occurred the caused so many storm sorcerers to appear in the region. In fact I see it as the part of FR with the highest concentration of most kinds of Sorcerers period, thanks to the Mulan Gods (Divine Souls), Shadovar and Shadar Kai (Shadow Magic), Great Rain (Storm Sorcerer), Dragon Bloodline (Chessenta, perhaps Cormyr), former areas of spellplague (Wild Magic).
You have large Theocracies (Mulhorand, Rasheman, Unther), Magicracies (Thay, what remains of High Imaskar, Rasheman), Olioarchies of merchants (Sembia, Vesperin), Democracy (Turmish), cities ruled by crime (Westgate), and a Confederacy where different cities use different styles of government (Chessenta), partial Elected Dragonborn Monarchy (Tymanther), more traditional Monarchies (Cormyr, some Chessenta city states, Impiltar, various sea kingdoms), Demiplane empires (High Imaskar's Celestial Nadir and the Kingdom of the Star Elves), whatever you'd call Algorond's style of Government.