That's a really damn good poster.
The size of the hand makes me think they're going with a child-aged X-23, and not the teenage streetwalker/assassin she is in the comics. Which is probably covering their ass in case they need to recast her if this movie tanks. The "badass + child" combo team is becoming really popular lately. I think it has something to do with all the nerds growing up and starting families.
One of the problems I've been having with the X-Men franchise at the moment is that, other than Wolverine, many of its major players are now time-locked into the 80s-90s. If they want to keep doing X-Men movies into, say, the 2020s, they'll either need to go with a new contemporary cast or keep doing "prequel" movies.
And I'm not sure how many more prequel movies they can do before they start to run into continuity snarls. It's already pretty messed up, with the time travel and the characters coming back from the dead...I mean, they never even bothered to explain how Xavier came back to life after X-Men 3 in order to appear in Days of Future Past.
Maybe they could do a New X-Men movie, and it'd have...Iceman and Colossus as team dads, with Quentin Quire as the bad guy and Deadpool, Cable, X-23 and Negasonic Teenage Warhead filling out the team. And Cyclops is headmaster now.
Not Xorn, though. Xorn was a fucking awful character.