I think there are some themes they could really play up - such as Jadis' description of the war with her sister and the use of the Deplorable Word. The scene in the garden with the apple at the end is another fantastic opportunity for some deeper storytelling.
Of course, these will all give Tilda a chance to shine - I can't think of anyone else who would be better for the role. It will also be pretty creepy to see her decked out as a beautiful queen, and not the scary creature that she ultimately becomes...
As dismayed as I was when I heard initially that SC was not going to be next, I've actually really warmed to the idea of having TMN as the fourth film. I think the story lends itself very easily to a movie adaption (VDT, by comparison, would have required a far bolder and more creative director than burnt-out Apted).
Also, it's got the best chance of truly revitalizing the franchise. The old BBC series did SC after VDT and then just lost all momentum. Perhaps there's a cautionary note, there. Maybe SC and LB will work a lot better as movies back-to-back, since they both involve Jill and Eustace.
Finally, although it can be regarded as the final part of the Caspian trilogy, SC happens so long afterwards and barely involves Caspian that it's a loose association at best.