Civ 5 certainly felt like it had a lot more meaningfulness to it. Civ 6 tries to amplify "action" by allowing people to either battle via Religious Combat or AI Combat. I'd agree that AI interaction is incredibly lacking in Civ 6. When Civ 6 first came out there was little reason to even interact with neighboring AI's.
With the latest DLC, I think the dev team has tried to bring back AI interaction with levels of diplomacy and communication (Alliances). I like Civ 6 because it feels like it has a lot more moving parts, but Civ 5 was more of a chess game and Civ 6 is more of an "action" game.