Well, thats hard to say, there are plenty of options. But it would have been nice to see further development of these 3 characters and their relationships throughout the story, which could have been a lot different than Ripley being alone again on the prisoner planet, the whole initial situation would have been different with Newt and Hicks on her side and there probably would have been a completely diverse plot, because of that. Although I can't think of one right now ^^
Of course, if one of them would have died during the film, it would have been a very emotional and dramatic scene...