It would be nice if a user could drag a font from MainType to FontCreator to open it for editing. I have another font manager not made by High-Logic, and it allows me to do this kind of drag and drop.
A context menu item to Open Fonts in FontCreator would be better. That would also work if FontCreator was currently closed, minimised, or hidden behind the MainType window.
Both features would be even better, because if implemented correctly, it would also allow drag and drop from MainType to any application that could deal with the font file.