If I'm to choose DLC theme, I would prefer Nine Hells, Snow zones, grim rainy forests, but defintely not Githayanki theme, I don't like their culture & how they look, not to mention their behaviour, though their behaviour is a good reason to kick their skinny butts.
A gith civil war sequel wouldn't take place just in gith places, they are a planar AND spelljammer civilisation, so you could be flying a stolen nautiloid or spelljammer ship around, fighting on different planets, caught in a three way,
O-V-MF war trying to stop other worlds being consumed in the crossfire? I'll just go back to the world sequel though, as it's both too big for a civil war and too dependent on characters and actions that the player might not take or have in their party?
Also Laez is better than Wyll/Karlach themed hell DLC as if you choose one side of the act 1 choice you lose those characters, but not all L play throughs will cause the civil war
A whole Gith sequel story could never even step food in a Gith building even..
Given the post-credits scene, I suspect D3 are the big bads of a sequel tho
