For some reason I thought she just didn't quite fit the part in the movie. I love Tilda Swanson and all, but when they dressed her up in lion fur and had her dual-wielding broadswords I was just like... come on, guys.

Her role in Prince Caspian was fitting, since she is mentioned in that scene in the book and it made for good film for her to appeal personally to Peter, whose own story was (not inappropriately) beefed up a little to convey his internal conflicts.

Regardless, I just worry that after a while they'll be replacing Tash with the White Witch and in the Last Battle she'll show up and yell "NEO! THIS WORLD IS MIIIIIIIINE!" And then the techno music starts playing and we get a slo-mo punch to the face by King Tirian as the climax to the fight and.....

you get my point.