You might want to check out Old World. It was created by Soren Johnson, lead designer on Civ4, and shares many similarities to that era of Civ while bringing in some new ideas as well.
I strongly disagree. Stacked units were utterly boring gameplay; one unit per tile made the military game actually fun for the first time in the series' history.
Civ 7 sucks and you should avoid it, but both 5 and 6 are quite good. They are significantly different from the previous entries due to the one unit per tile system, but different for the better imo.