In the past I generally would only install the OS, Tools and Utilities on the Workbench SYS: partition. Apps otherwise would be on the Work: partition. That way i could re-install the OS without needing to do much with the other apps. It would be nice if during the installation we could decide to have the installation use a split partition approach. It could be managed with an assign command to point to a different partition.

Yes, back in the times I had similar setup. One partition for OS, the other one for apps. However such split was just a fiction. Many apps installed their custom gadgets, libraries, catalogs and many other files onto the OS partition. If you later erased the OS partition and installed a clean OS there, the apps located on the other partition stopped working... because their custom files were not on the OS partition anymore, you know.