Taste is subjective. And there are decks which have more in them than some people realize. Just as in literature or any other art, some works are recognized as good or great by many people and many are dismissed as being lesser. Some of those generally considered lesser may be thought great by a few people who see in them something the majority don't see.
But just as in literature, someone somewhere had to start the credentials by which a work is considered "good." Topic? Style? Execution? All these factors have been used as touchstones for assessing the arts. But every rule has been broken often by creators whose work has since become recognized as better than anyone once thought. (Consider what Gregory said about Beethoven et al.)
Much of what I'm saying is paraphrased from C.S. Lewis's book An Experiment in Criticism, which I wish were required reading for every literature and fine arts department in the country, if not the world. He speaks mainly of literature, but agrees that the concept is applicable to any art form.
And what is Tarot but an art form? Visual, meditative, whatever: creating a deck is an art, or a combination of arts; using a deck to read or meditate is an appreciation of art, along with whatever appreciation is given to the actual visual images as art. (Lewis would make a distinction between appreciating art and using art, but that's a whole other tangent.)
So, yes, some decks probably are better than others, but much depends on who's doing the judging, and by what criteria. If, as Lewis says of popular books, even one person takes the simplistic-seeming knockoff-seeming (and we can seldom tell for sure if a deck was just knocked off or labored over for years) deck and has profound meditative experiences with it or reads beautifully with it, and would be desolate if anything were to happen to it, "we should not dare to put it beyond the pale."