What you are talking about is an original character book, like Peter David's New Frontier books. There is nothing wrong with that desire, it's just not "Voyager". Next Gen books need to be about Next Gen characters, and the same with DS9 and Voyager. There are whole groups of people that buy Voyager books and expect to read about Voyager characters.
Perhaps one of the author's will set new characters on another Intrepid Starship.