I have had some discussions with Nick Birkett-Smith the Product Definition Manager for Assemblies. We came up with an enhancement that could significantly save time for users who use SSP or Master Modeling. If you ever have parts linked to a SSP or Master Sketch and wished you could move them to another assembly when changes come in this SPR is for you. Please read below for Nick's summary and vote if you believe it will help you.
SPR 1098704 "Top down modelling - ability to move (reorganize) a component from sub-assembly A to sub-assy B, and remap that component's external references from a master (skeleton) part in sub-assy A to a master part in sub-assy B."