This has been asked for multiple times in the past. Rather than having just shared choices that can never be changed, create a second class of shared choices (call them whatever you would like) that are just templates. This would be useful for standard colors etc. This template can be applied as a choice or modifier but can be edited on a per product basis. It's just a huge timesaver as it's much easier to delete a few items from a master list than have to continually recreate effectivel the same list. Right now a user has to clone a product with similar features which requires much planning.