Faster unload would be nice.
More maneuverable, maybe sharper turning rear axle or even have the tracks steer the opposite direction as the rear axle.
Different threshing drive for APS, cylinder, and impeller. I don't like the two speed drive as soybean harvest is often needed to run on both sides of the ranges. Furthermore, it isn't reversible, which isn't critical for me anymore (don't hardly ever choke it) but would be nice. I think electric drive would be nice here, or cvt or something.
Also, could benefit from clean grain slow down kit for crops other than corn. Everything else does not need a 6000 bph setup.