How much can you change a setting before it becomes something else?
I just saw the second trailer for the new The Three Musketeers and it looks (a) barking mad and (b) not much like The Three Musketeers except in basic outline, as its big standout action scene involves airships firing broadsides at each other, a mere century and a half before the Montgolfier brothers' first flight. It looks more like the counterhistorical slam-all-the-most-fun-eras-together setting of 7th Sea than anything.
As a historian, this might bug me, but it does it with a big goofy smile on its face. It isn't presenting itself as a historical drama (like Braveheart to pick my least favourite example) any more than X-Men: First Class is the true story of the Cuban Missile Crisis. After all, The Three Musketeers itself didn't really happen.
But anyway, if I signed on for a swashbuckling game and there were century-early airships, or voodoo turned out to actually work, I'd want "this is going to be a bit mad" to be signposted fairly early. Which showing airships firing broadsides at each other in the trailer achieves. And equally, I'd want to be able to swash said buckler in this new situation, and be able to swing from airship to airship as readily as swing from regular ship to regular ship. The setting may have gone wonky, but I can still get my swashbuckler on and be useful in it.
(7th Sea does bug me, but mostly for plundering the good bits of history and divorcing them all from context by putting them in a non-Earth setting... and making pirates a supplement...)