Few things I’d love to see in world machine:
Auto-save feature, were you can set up a time interval and a number of files that will be saved in a predefined folder, maybe documents, like the scripts folder.
Incremental save of scene file as an option will also add safety and option to track progress.
3D preview windows could have higher resolutions for real time preview, even though it would be much slower to refresh, it could be a user option.
3D preview, ( or any work view ) as a floating window, so it could be put aside in the same or other monitor.
That`s all I can think of now, want also to congratulate you for this amazing yet extremely simple to learn and use software, World machine really made me believe that there are incredible people in this world making good stuff for accessible prices.