I'm not real familiar with X-23 either, but I mainly remember seeing her show up on the old X-Men Evolutions cartoon. I've seen her mentioned in the comic world, but I don't really read X-Men comics (or hers) so I don't know. From what I gather, she's sort of a female version of Wolverine (with claws), she might even be a clone? Others probably know much more than I do though.
I think these two waves will be pretty light for me as well. I think Iron Fist is the only tempting one from 12, but I don't know that I necessarily "need" that one either. Wave 13 is a little more tempting with the villains, but I'm not sure which ones I will pick up. I'll likely get the Goblin if it is good, since I still don't have one. Really, waves 11, 12, and 13 aren't overly exciting to me. There are some good figures in each, but the "waves" don't seem quite as good as they used to. I guess that is in part because so many characters have been done already. At least some people are getting some of their own requested figures though. I wonder how much "juice" the ML line has left in it? Certainly there are a number of characters left to do, just depending on which ones ToyBiz chooses to make.