There are a lot of speculations about the upcoming DLC, especially the recent “leak” of an US Civ. Some are hyped (like Drongo), but most people in the forum are firmly against the USA starting in age 1 (me included). But i dont think this will ever happen.
the Devs are well aware about the game and its design. Particularly in the last Patch, they did amazing work and implemented very intelligent ballance changes. I dont think they are high on acid and start the mess of making revolutions into regular civs (especially with all the south american fanboys).
except of steamdb, all hints lead to an Italy/Ethiopia/… DLC. The Units (and buildings) in the historical battles are african and the ones in the screenshots are italy. Besides that, italy was meant to be in vanilla and is the most demanded. The devs wont dissapoint the playerbase in these regards.
“But what about steamdb?”
After the release of DE, i was pretty happy about the changes with the revolutions, although they still seamed not competitive. All revolutionaires had different names, but mostly the same skin and stats. With the patches they added mechanics and beautifull new skins (Dorobant, Hungarian Huss…) and i wondered, why they put this much effort into something, most players will never see. After the steamdb ‘leak’ i’m pretty confident, they will make the revolutions much more viable and add even more new mechanics and units (maybe more revolutions as well, since Italy would need something else besides rev. into barbary coast). I think the US will be the poster child of this DLC, but still stay a revolutionary Civ.
TLDR: Next DLC will be Africa/Italy. In addition we get better revolutions via USA FLC. (i dont think, they’ll compine the Africa DLC with the Rev. changes)