I have great fun playing the game but a great part of it is also the visuals. Did you ever realize that we all look at cars in the same way; as sexual objects? Example: "nice shape, love the color, what a sound, looks great from the rear, smell the leather" and the most common, "I can't take my eyes from it". Although you may not admit it, the visual aspect of looking at cars in their environment is significant, maybe since you were 9 years old like me. Of course, physics made this game but let us not forget the hours spent replaying the races and taking pictures. It was because of this automotive "eye candy".
I could see in the survey many will go for the AI and physics, and in essence I agree, but I believe the graphics need to be raised to the level of that other half of the game. While I play, these graphic shortcuts distract me. The strobe-like pixelated shadows, low resolution texture maps, low polygon "cardboard" people and trees. I hate it, but "we need to compromise". I could live for now with the existing AI, physics, sound and existing mods but the graphics are killing me. So, if I had to choose only one option, then my vote goes to: Track Detail / More polygons / no popups