It would be useful to be able to customize the properties of the auto generated RadSplitContainer, RadPaneGroup and ToolWindow instances (created by floating, docking, pinning and unpinning of RadPane instances) based on the old RadPane instance. For example the GeneratedItemsFactory methods could provide information about the RadPane for which SplitContainer etc is created. Available in the 2016 R2 release.
Yes, we would have needed this feature as well.