X-23 is not ready for the timeline of Wolverine at the moment, you may be able to introduce her at the end of Wolverine 3, but then as only a cameo... If you want a story with her in it, you'd wanna see a new or young x-men movie based on the later comics...
I think she is a good character but the current feel of the x-men in the movies is very much the classic x-men from the 80's to 90's for X-23 is a 00's era of x-men the movies need to catch up with that time line. Now you may argue that the elementsused in x-men 3 was 00's but look at the story it wasnt great was it. and that was only one element they took from the 00's era