The thing that needs to be understood is that Donna has never been considered a part of the Wonderverse on an editorial level. She was created to be a Teen Titan, editorial places her under the Teen Titans umbrella, and since Wonder Woman has never shared an editorial office with Teen Titans, any time Donna is used in the main title requires getting special permission from a seperate branch of editorial and running the entire script by them for approval on every little thing.
This is unlike Yara and Nubia who created in Wonder Womans own book, have not been grabbed up by a different branch of editorial, thus creatives are allowed to use them without playing a game of telephone with multiple editorial offices.