Kaplan's quote from Waite's autobiography is very telling. I'll post the whole thing for reference.
"The Secret Tradition in Goetia was my first considerable work bearing the Rider imprint; but it was preceded in 1910 by a delightful experiment with the so-called Tarot Divinatory Cards, otherwise denominated the Book of Thoth in the high fantasia of my old friend Eliphas Levi. Now in those days there was a most imaginative and abnormally psychic artist, named Pamela Colman Smith, who had drifted into the Golden Dawn and loved the Ceremonies - as transformed by myself - without pretending or indeed attempting to understand their subsurface consequence. It seemed to some of us in the circle that there was a draughtswoman among us who, under proper guidance, could produce a Tarot with an appeal in the world of art and a suggestion of significance behind the Symbols which would put on them another construction than had ever been dreamed by those who, through many generations, had produced and used them for mere divinatory purposes. My province was to see that the designs - especially those of the important Trumps Major kept that in the hidenness which belonged to certain Greater Mysteries, in the Paths of which I was travelling. I am not of course intimating that the Golden Dawn had any deep understanding by inheritance of Tarot Cards; but, if I may so say, it was getting to know under my auspices that their Symbols -- or some at least among them -- were gates which opened on realms of vision beyond occult dreams. I saw to it therefore that Pamela Colman Smith should not be picking up casually any floating images from my own or another mind. She had to be spoon-fed carefully over the Priestess Card, over that which is called the Fool and over the Hanged Man"
From this several points can be gleaned.
1. Pamela "drifted" into the GD after Waite had already transformed the GD ceremonies.
2. She was abnormally psychic and a good artist.
3. She didn't really understand the occult significance of the ceremonies.
4. Waite intended to construct a deck that was more than a mere divination tool.
By the time Pamela came along, Waite had already moved the GD in a drastically different direction. Under Mathers and Westcott, its primary focus where Tarot was concerned was divination. Waite saw the Tarot as a doorway to mystic visions and direct revelation.
Waite says the GD generally didn't have a "deep understanding" of Tarot, he thought his was deeper at any rate. Nevertheless he felt obligated to keep Pamela in the dark concerning any GD secrets she might pick up psychically. Therefore he spoon-fed her what he wanted her to know, and directed her to make the Majors the way he wanted them so she wouldn't accidentally reveal something.
In conclusion, his primary mission was to create an artistically interesting deck that could be used for meditation. He wasn't trying to conceal any deep dark GD secrets, he was going in an entirely different direction. The deck shows some GD influence but that's about as far as it goes.