At the moment, replacing work features (e.g. planes) is time-consuming as you have to hunt through the tree trying to find every place where it is used and then reworking each command. You can try and delete it which will show each command that is affected but this doesn't work if the work feature is derived from another part, which happens a lot with skeleton modelling.
It would be much quicker if you could right-click on the work feature and have an option to Replace, and then select the new feature, and this would replace all references to the first work feature with the second one. I know this is possible, Catia does it...
On a related note, if you redefine a sketch onto a new plane, all projected geometry in that sketch should stay referenced- at the moment it doesn't, and if you want a fully-constrained sketch you have to go through and reproject in all the geometry. Again, Catia...