The Steam Workshop for Civ 5 is still active, offering hundreds of total conversion mods, map updates, and UI enhancements.
This expansion reintroduced religion as a core mechanic. Players could found pantheons and eventually create their own customized religions. You could choose beliefs that boosted your economy, happiness, or military production. A player could found "Catholicism" with beliefs that generate gold from shrines, or "Buddhism" focused on spreading peace and happiness. Religion became a tool for soft power, influencing neighboring civilizations and city-states without firing a shot. civilization 5 complete edition