Don't have to do her as a clone just a young girl with his powers. There is a reason I would want her in.
It's a prequel so the kids from X-men 1 can not be in it. They need to show that after everything that happened Wolverine still has his good side (even if he never admits it)
The best way to show this later in the film introduce X-23 so he sees a young kid going through the stuff he himself has been through. This also allows for a relationship similar to his connection with Rouge in first film.
At the end she can disappear , leave or be killed. But showing that connection will help make the good qualities of Wolverine show and not just his "grrr look at my claws" side.
Also this will help show that Stryker and the whole Weapon X thing don't care if you are a grown man or a young girtl , If they can experiment on you , they will do.
Which yes we already know it from X-men 2 when he did the mind control thing to his own son BUT we also need assume that some people who see Wolverine might not of seen the X-men films.
Also wouldn't help to remind the people who did see those film what heartless bastards they are and in doing that it will also help people care more about wolverine's escape and quest.
Then if they ever do an X-men 4 they can have X-23 join the school (might not in comics I'm not sure but the films are different and that could be cool)
