I grew up playing III but never really understood it I guess until I came back to it more recently as an adult after playing far too much of IV, V and VI. I like III a lot I think because your toolkit is more limited and the efficiency of your play is more important, which is the part of the game I enjoy the most maybe. In the newer ones you have too many options to win and ways to get out of situations, and the AI can’t utilize most game systems very well it seems. The high difficulties in III are a real challenge and the mechanics feel good and logical to me once you get to know them. Maybe also some nostalgia with the soundtrack and graphics.