I felt the film franchise had finally hit its stride with Dawn Treader. I was looking forward to The Silver Chair, while at the same time hoping they never made the Last Battle (I have issues with the book, but if you like it, fine). The Greco-Roman and Christian allegories in the books irk people now in a way they did not back then. Personally, I enjoy it. It doesn't have to move away from that. I felt the recent films had a decent enough footing.
It's easy to see the heavy handed writing of the Calormen being evil swarthy heathen people of color. Lewis didn't even try hard on that one. Horse and His Boy is going to be a tough sell. And of course Susan not making it to Narnian heaven because she liked to apply makeup and had a healthy interest in boys her age says more about the state of Lewis's mind when he finished his series than I want to delve into. It's not going to be easy to make a 2020 Narnia. Some might think it not even a great idea when they are arguably better fantasy alternatives on the library shelves (I would love to see Brian Aldiss's Helliconia series make it to the screen, personally). But I suppose for any of us that cracked those books open as a child, there's a room in our minds where that wardrobe still sits and waits.
2 years though, sheesh.