At the moment you design in an assembly workspace, what I'd like is separate Assembly Workspaces like the animate workspace with no modeling tools, just joints. I don't see any reason you couldn't have several Assembly workspaces as well.
I see a couple of uses for this.
One, you can experiment with an assembly without affecting the modeling workspace assembly so your 2d drawings don't get messed up or adding complications to the modeling process in the modeling workspace. Could also be useful for 2d assembly drawings.
Two, for CAM work. You'd be able to layout parts for machining without affecting your design. I guess you'd need the ability to make copies of components as well for this to be really useful. Under the CAM Root in the CAM environment you'd have the option to select one of the Assembly Workspaces instead of the Model workspace.
Thanks Mark