With the main focus of the game is automation and optimization, (in my opinion) the game should be most difficult/challenging in that area. I can't think of a way to word this properly, but I believe that conveyors should have collision detection with other conveyors. In my first 11 hours in the grassy hills, I found that logistics is significantly easier if I ignore any signs of improper use of conveyors, such as crossing or blending the conveyors; this really detracted from my experience.
Also, if you stand on a truck in the wrong place, it'll swerve or flip, etc.