For example, in Civ 6 establishing trade routes becomes really important, but it's impossible to automate. So EVERY time a trader finishes a route you must MANUALLY select which city to trade with. By endgame you're clicking through a dozen trade routes every turn.
Also, unless you decide to annihilate everyone prepare for NPCs to constantly pester you with stupid requests, like trading your capital for a resource of peaches. And then they can keep repeating the same requests. Why can't I just set my disposition to always automatically deny all incoming requests?
The waging war by religion seems incomplete too, you only have two unit types: apostles and missionaries.
I recommend 6 overall but Civ 1 doesn't overcomplicate it, it's still as great today as it was back then.