This isn't by any means a weakness. Quite a few writers ring effective changes on the skin-deep, and Dickens gets a lot of mileage out of his eccentrics. (His most lasting character of any depth is the city of London, too, and its many voices.) A CHRISTMAS CAROL draws its strength from the promise of redemption, and surely the fact that its spirits are familiars. Dickens himself was enormously entertained in the writing of it, and years later, reading it aloud and playing all the parts, for his immediate family or for a paying audience, he relished every cadence and effect. The story's got staying power. Nor do I think it's any real stretch to say Dickens effectively invented our idea of Christmas, or at least embodied it. He wasn't the first guy to write about it, and A CHRISTMAS CAROL wasn't his first shot - or the last, either - but it's the one that sticks to your ribs. And it's bulletproof. You can't fix it because it ain't broke. I was in 5th or 6th grade when I saw an adaption the 8th grade put on, and I was transported by it. Scrooge McDuck, or Alistair Sim. It goes the distance, and it's impervious to harm. That's the test. That it seems both faithful and new, every time.
The 'mystery' of Dickens - if you choose to put it that way, and I will - isn't the unfinished DROOD, or putting his wife out to pasture, in favor of an unsuitable attachment, or the most curious incident of the Staplehurst railway crash, blind chance saving his life. The mystery is his fresh eye. Dickens is not original, in the sense of discovery, but he reimagines the known, turning it back to front. What's different about him, and the difference he makes, is that he has a way of seeing the world, both in detail and in large. He uses, in effect, camera movement. He pulls focus. He approximates the zoom lens, or the dolly shot. Dickens was fascinated by the theater, by all kinds of stage business, tricks of the trade. How did he come by this sensibility, that I'd call cinematic? There's no analog for it, technologically, in his era. And yet Dickens seems so much of his time, a representative figure. I can't account for it. The pleasure is in the writing.