As for trying to come up with the five things that I like the most, I would compile this list by trying to determine what I would miss the most if I no longer had it. In trying to do that, I came up with a lot more than five items.

As for the things I would like to see, I offer the following.

The Realistic Sky option was certainly a step forward; however it was only a step. There is certainly a lot more that can be done here. I would like to be able to generate sun rays steaming across the sky. The clouds were improved in 4.03, but it would be even better if they would also interact with other lights in the scene.

The cloud objects also could be improved. Carrara still has a ways to go to match Terragen skys.

The plants could be improved by providing an option to allow the branches to bend. Currently you can adjust the curvature and elasticity, but branches can also have localized radical bends in them. An option to provide this would be nice.

I would also like to see additional modeling tools in the vertex modeler. Providing an easy method for selecting vertices on only the face of an object which is showing would be really nice. Also, the motion vectors that were added in the assembly room for moving objects would be nice to have for moving a single point or poly in the vertex modeler.

But most of all, I would like to see a distance option that would fade the color of objects based on their distance from the camera.