It would need to support scanned data.
It should include support for MMF (meal master format)
MMF, RTF, HTML, and maybe XML export. Definitely Palm OS pdb export
Import from MS Word or RTF
Search on recipes, ingredients, techniques in the directions
Drag and drop cookbook building, by recipe or file
spell check, complete with all the foreign terms common to cooking
Automatic indexing on recipe ingredients and recipe titles
User defined linking to designate all recipes used in a certain menu, including overlap of some recipes for multiple menus. Or for just well related recipes, say a meat dish and a sauce. or building a wine list of wines to keep on hand.
Mis en place extraction from the recipe ingredients. Yes, this is out there a ways.
Multiple simultaneous recipe display (for comparison purpose)
A recipe editor of course
Full configuration of formatting. Size, font, page sizes, columns, ingredients at the first or spread out through the body of the recipe as the user prefers.
The ability to print just recipes or full cookbooks
One of the fields should be the source so proper credit can be given. this field should be searchable.
An internet ability to launch a browser and maintain an extensive list of cooking references and links.
Probably more ideas later.