Backwards

CiV is as of current broken in half on high difficulties.

Apparently it has REX syndrome worse than CivIII; you can keep settling onto tundra to happiness limit and it does not matter because they are powered by maritime food engine and you just run libraries/specialists in all of them.

The AI is also notorious for its terrible tactical awareness. This is counteracted by its production bonuses as you crank up the difficulty.

"This is feeling less strategic and more tower defense."

Interestingly enough, this runs counter to their selling points of less cities, more strategic combat.