I find the principle of abrogation from islam particularly odd; there is a common myth in many religions, where the hero is put to a test by his deity; if the hero passes the test then the hero is good and dandy, otherwise he is an anti-hero. In the verses that support abrogation, the deity acts as a liar and the hero accepts the truth of that claim. In other words, the hero accepts as a fact that his deity is immoral. Within religious bounds, I see only two possible conclusions: either the deity is actually immoral, or the hero has failed the test miserably. As far as I know, because the islamic deity first claimed to be the Judeo-Christian god, muhammad has to be a false prophet. On the other hand, muslims believe that the life of muhammad is the model for a perfect life. Another point is that all muslims are expected to go to Mecca.
To me, the only way to have some consistency is to look at the life of muhammad in reverse chronological order (ie. the part from Medina represents the state of the fallen man, while the part from Mecca represents what the man has to become).
That POV doesn't strike me as something original, so my question would be on why this hasn't already become the mainstream interpretation of the islamic texts. My best interpretation is that the political leaders, when confronted with this POV, preferred to repress it as a choice between having an army with no cohesion because everybody is expected to be a liar vs. having an army with no desire to fight against non-muslim neighbors. This interpretation would be consistent with the endless fights for the leading position within muslims.
Maybe i'm just over-generalizing here, but for many people the religious experience is the deepest form of self they are ever going to experience. If there is something that rejects universal ethics right at the core of a human soul, the tension should be pretty high and a unifying POV should spread quite easily.