I get what your saying, adding more sizes are not our problem, I can do that, but adding a new feature to the part or removing one is something that comes up a lot. Example, and work point needs to now be added to a family of parts so that routing hoses and or harnesses is easier by having a point to snap to, but the only way we can figure out how to do this is to delete the family out, ad the feature to the ipart, re-publish the part and replace every instance of the older family ipart with the new one.... a lot of work to simply add in a workpoint
IV 2010 SP3