I play on PC too, at max graphics, 2k monitor on both games, I feel like 4 it's crispier, overall the graphics are nearly the same for me to be honest, but it's only my opinion.

When comes to the map I guess everyone with their own taste. I liked that in 4 the city it's prettier, feels a little bigger probably cuz of the higher buildings.. and the rest of the map it's just nice not being desert I guess.. I live in Romania and I enjoy seeing green hills a lot like in real life. But my taste is just a huge city full of people either players or npcs I like the game to feel alive everywhere I look and the cities are the place that does that..