There is also an intrinsic tension between the concept of Prophets receiving divine revelation (which must therefore be true) and that revelation being continuing, which allows it to be revised. To reconcile this, you need to go back and decide that the earlier one must have either been incorrect, and therefore not really revelation, or that everyone was interpreting it wrong all along. Needless to say, this adds to the confusion.
Finally, a given statement may be regarded by some as doctrine, and others as policy, and this itself can be a point of disagreement.
You've got the scripture, including The Old and New Testaments, as well as the Book of Mormon, Doctrine and Covenants, and Pearl of Great Price. Of course you have a problem right there, because these documents are not consistent, but at least you know what's in the mix.
Then you've got revelation from the Prophets. Again, same problem. The more of them you get, the more likely to conflict with the above and each other. There's a lot of wiggle room there, because you can consider something doctrine, get a new revelation that's different, and go back and realize it wasn't doctrine after all. Convenient, that.
Anyway, while all this is rife with problem, it's also rather cool and different from other churches. It makes the Mormon Church more flexible and adaptable, which I believe has contributed to its success. If you look at it from the point of view of meme theory, it allows the meme of Mormonism to evolve more quickly than other religious memes. However, it also means that Mormonism today looks very different from Mormonism of 150 years ago.