I read the Narnia books and I like them, but I'll admit I had a big problem with the fauns, nymphs and Bacchus, because of their pagan, idol-worshipping, evil origin. If he would have kept Bacchus and the drunkenness out, it would have been much better.
Also, Lewis was sexist about the magicians in his series. If the magic-user was female, she was automatically a wicked witch. But if the magic-user was male, there was a chance he could be a good wizard. I thought magic use was forbidden by the Bible, why do Christians write stories about good wizards? I've read other books written by Christians with good magicians in it. Lord of the Rings by Tolkein, and Donita K. Paul's dragon riders series. There's also Stephen Lawhead's Pendragon series.
I guess you are a fantasy hater. That's too bad. There are many good fantasy books and movies that glorify the Lord. Fantasy gives us a glimpse of heaven. It stretches are imagination. The Bible could be considered a wonderful work of fantasy. Of course, the Bible is true, but it has fantastic imagery. Read Revelations, and some of the prophecies in Ezekiel and Daniel.
I write fantasy stories. In my stories it is usually the bad guys that use magic. The heroes might have miracle-magic, some sort of Holy Spirit power, usually my heroes are Christians. They are not always human though. I like to write and imaginary fantasy creatures. I have good Christian dragon characters, fairies, elves, unicorns and mermaids/mermen. Sometimes I borrow themes from traditional fairy tales. I often make it clear in my stories that my characters are Christians and that it is Jehovah God and His son Jesus Christ they are worshiping.