enhanced UX experience for content editors. esp taking the most generically useful UX enhancements of Castle, and putting them in the core so castle doesn’t have to maintain them. Toolbar enhancements and the placeless adding come to mine, but you guys know what your users like more than anyone else right? (or maybe its what you no longer get support requests for anymore?)
Perhaps work on Mosaic or a mosaic replacement is a part of that too?