Well I am a tad late to the conversation but it's most fascinating, and I agree with those who decree, "use the cards as you please." If we are to get more specific, then on all counts I agree with closrapexa. And I say what I am about to say with the disclaimer that I agree that intense study should be kept behind the scenes and out of the reading (when reading for others), unless the querent inquires so deeply as to desire/require it. A great depth of study is most useful as fodder for the reader; s/he should not ramble on and on about it during the actual reading, as it is confusing. Take time to consider it if needed, then speak only what is necessary.
I think it’s presumptuous to say that we’ve only recently begun “overcomplicating” things. Realistically, we only have a vague idea of tarot’s history, and there’s no real way of knowing all the myriad ways it may or may not have been used across various cultures throughout history (and, as was mentioned, behind closed doors); we only know what we know, and cannot disprove what we do not know. I think it’s more than likely that people have been “overcomplicating” tarot for centuries; our general understanding is that various forms of astrology and Kaballah and numerology and most other systems now being regularly cross-referenced with tarot (with the exception of the more recent addition of Jungian psychology and any other modern systems) predate tarot by very long stretches of time. To think that only in the past few decades have we begun to draw conclusions and cross-reference tarot with various metaphysical systems of understanding our universe would be naive; we’re merely the first ones to write about it to such a degree and with such fervor (at least with the in-your-face marketing of today’s tarot literature; I’m sure plenty of authors touched down on some of these things prior to whatever’s currently in print, and we just can’t find much of it easily anymore).
One could argue that it’s actually the other way around: that tarot itself, having come later than all these other systems, is itself a system of understanding the world that “overcomplicates” things. We already had all these other systems; why invent the tarot? Or rather, why use cards as something other than a game? Because someone noticed a pattern. Anything in life only has meaning because meaning was given to it. Meaning is merely a way of understanding life, the self, god, what have you. So we had all these other systems, and then someone noticed that there existed a new kind of pattern in the universe, and applied that meaning to these cards. They shared this discovery with others, and/or others picked up on the similarity themselves. Eventually, a whole new system, tarot, had been developed (whether or not it was first a game is beside the point; we're talking about how cards came to be "read," and that certainly happened, one way or another, because of these observations). Tarot itself is a result of overcomplication of meaning. Which is not a bad thing; it's just something that happens naturally the more people think and ideate. Despite it being a newer complication, tarot is fascinating and still a relevant representation of truth, just as these various other systems are all relevant representations of truth, in some way. We conceived of all these things, and so they have meaning, at least to some.
None of this cross-referencing is necessary to read tarot cards, of course. Tarot is like life (clearly), and like life, we can go as deep with it as we choose. Or not. It really depends on how we’re using the cards, and there’s really no right or wrong way to use them. Though, as was already stated, so-called ‘basic’ tarot meanings have a source, and that source ought to be questioned so that an individual can decide what this system really means to THEM. Which is why all this literature exists. And that is the question one must ask of oneself: what does tarot mean to YOU? And are you satisfied with someone else’s idea of what it means or how to read the cards? And how did you decide that one person’s idea (because those ‘basic’ meanings WERE someone’s idea, or a bunch of ideas mashed together over time for convenience) is more relevant than another person’s idea? And if the answer is, “well because that's the meaning that came first,” (was it?) or at least “it’s the first one I learned,” or “it’s the one I’ve heard the most,” then it’s worth examining why you would accept the first version of truth that you learned and reject any subsequent interpretations.
In short, we have not overcomplicated tarot. Tarot itself arose as a complication, a need to further explain the mysteries of life when there were already many other systems in place for this, and if anything, many have got it backwards: those "basic", or "classic" tarot meanings are, to one degree or another, an oversimplification of meanings that were assigned by many and passed down over a long period of time, and those simplified meanings were then repeated over and over in various books and reading circles. The fact that we are mixing other systems in so liberally is neither a new development nor a need for concern; it is the attempt of those who are still paying close attention to correct what may be deemed an oversimplification and say, no, in fact there IS more to tarot—or life—than that, if you choose to see the patterns.
If, however, you have looked around and become overwhelmed by what’s out there, or tried other methods, and found that a more simple method of reading is the one that works best for you, then by all means stick with it! Because of course, the most important thing while doing anything in life is to be true to oneself.