The main obstacles to learning Kabalah are  the books that purportedly  give simple introductions to Kabalah.
I can't go into the many ways of learning Kabalah in the wrong way right now. But I will spend a few minutes trying to convince people to learn it the right way.

Obviously the first step is the have a solid background in Talmud and Torah. But after that the basic step is the Eitz Chaim [the book called the Tree of Life, עץ חיים] of the Ari  [Isaac Luria (האריז''ל)].
This is an extremely simple book, and easy to understand on the very first reading. All the introductions to it only make what is simple sound complex. And usually they are trying to expand their own agenda in the name of Kabalah. All kabalistic ashkenazic books have this serious flaw, and are because of this less than worthless.
Where the Ari gets difficult is when you get to the Eight Gates and try to apply its world view to the verse of the Torah. [Later note: I was trying to say that how the Ari applies his system to any particular verse of subject is  things get complicated. My advice for this problem is to first learn all the writings o the Ari in order from the beginning to end. That is the Eitz Chaim, Pri Eitz Chaim, and the whole set of  the Eight Gates. Altogether that is about twenty books. The way to do that is to have place marker and to read a little every day until you turn the page. Put in the place marker and the second day start from where you left off. It takes some time but eventually you get through it. And don't take any Kabalah classes for heavens sake. Not only will you learn nothing from them but they are traps to entice you into different cults.  ]

However I should mention the Reshash (רש''ש) (R. Shalom Sharabi). He has a pretty good system, but it seems to me that it should be reserved for a fourth year or graduate kabalah student.
The Reshash  is not the simple explanation of the Ari. And the simple explanation (not like the Reshash) of the Ari is how the Ramchal (רמח''ל) [Moshe Chaim Lutzato] understands the Ari and also  Yaakov Avuchatzaira. And it is largely based on an essay that he brings that is not a part of the canonical books of the Ari. (דרוש הדעת)
If you do not have the Eitz Chaim, or want a different approach, the Mavo Shearim (מבוא שערים) is a parallel version of the same, and also pretty good. Personally, I think nothing can compare with the Eitz  Chaim as a masterpiece of power and beauty.
 Incidentally, the system of the Ari is a highly evolved Neo Platonic system as so it is not to be expected that any Protestants can understand it. You need to have intuitively a Platonic world view in order to understand Kabalah. Also the Protestant bias against the very idea of keeping mitzvas stands in the way of understanding Kabalah. [Understanding spiritual light that doing mitzvahs as cause to bring into the world is a basic function of Kabalah. If.If you think as Protestants do that mitzvahs are worthless relics of a bygone era then there is no way they can understand what the kabalah is trying to accomplish.]
Now, I know the Rambam is highly Aristotelian and it does sees a mystic understanding of the Rambam is possible as we see in Avraham Abulafia. However in this essay here I am referring on to the Ari.

[Also I should mention that it is in fact in the Reshash that you find the two systems of Plato and Aristotle combined. In the  view of the Reshash all the higher worlds of the Forms become horizontal Universals contained in "things in themselves." (Dinge An Sich)]

Also I should mention that university Kabalah is Medieval Kabalah  and has nothing to do with the Ari'zal (Issaac Luria). It is an interesting subject in itself, but it is not what I am talking about in this essay. Gershom Sholem [The Professor at Hebrew University that made medieval  Kabalah into a respectable academic discipline] and his followers simply were doing work in a different area than the kabalah of Isaac Luria and Moshe Kordovaro.
It does seem to be likely that Hegel did some amount of borrowing from the Ari and put it into rational and philosophic terminology. Actually Hegel seems mostly to be like the Reshash with his triadic system. But I can't imagine Hegel had heard of the Reshash. But Hegel certainly did borrow from the Ari. So maybe it is just that both Hegel and the Reshash both came to the same conclusions based on the Ari. Though Hegel to it in the direction of Metaphysics