Judeo-Christian scriptures in Islam; A clear Message?: Letter pt. 2

This is the 2nd part of a letter to my Muslim convert friend. I have not included his well-argued letter as I haven't his permission as yet.
The scripturesI particularly enjoyed your well researched and thought-provoking section on the Judeo-Christian scriptures. As I understand it, Islam teaches that the God of these scriptures is the same as the God of Islam. In fact, is it not true that Muslims believe that Muhammad’s arrival was prophesied in the Old Testament by God’s prophets, in the same way that Christians believe the coming of Christ was the fulfilment of the prophesies in the same scriptures? Am I also right in thinking that you believe in the literal truth of the Torah/ Pentateuch?
(with the rider that certain changes have taken place because the Chosen People didn’t look after it carefully enough and/or changed it because they were untrustworthy Jews. I’m just quoting the Qur’an here, you know...the People of the Book are the Jews, aren’t they? [Surah 3:78 and 5:14-15]) This being the case, I am unsure why you seem keen to highlight the blood-thirsty and vengeful nature of the God of the Old Testament (Deuteronomy 13:6-10, Numbers 31: 17-18). Surely this is the very same God that Muslims worship! In your haste to show how merciful Allah is by comparison, you seem to forget that it’s the Allah of Islam ordering the death of every male child and suggesting the virgins are kept back for later enjoyment. Or perhaps you think this is a case where the Jews have made some of those wicked changes? But doesn’t it seem strange that they should have changed the scripture to make their God sound more cruel and vengeful than he really is? Aren’t you simply doing what modern-day liberal Christians do, and cherry-picking the Pentateuch for those bits that fit in with your beliefs whilst ignoring those awkward sections that sound just a bit sexist/weird/too bloody and violent for modern tastes? Why believe in 800 year-old patriarchs, men being swallowed up by whales, an old man saving the entire world’s fauna by loading it onto a boat, talking snakes etc. because it’s in a millennia-old scripture, but not in a vengeful and blood-thirsty God in the same book? Or, and this is stretching it a bit, perhaps you believe the Jews changed these bits to justify their behavior? But if you allow that, then mustn’t you also allow the possibility that Mohammad made up some of the surah to justify/excuse his own exclusion from some of the more onerous restrictions about marrying relatives: surah 33:50 for example?You see, if one approaches all of these old scriptures with an open mind, then these are the doubts that assail one. Is it wrong to wonder and question? Is it wrong to reach one’s own conclusions based on the available evidence?
Clarity of message
The third point is also a recurring frustration (you’ll see there are quite a few of these...apologies) which you actually allude to during your brief comparison of the history of the Bible and the Qur’an (by the way, please don’t think that I am in any way more of a supporter of the Christianity of the Old Testament than the Islam of the Qur’an.) What you seem to be saying in this section of your letter, in addition to the above, is that the Qur’an is a more reliable testament than the Judeo-Christian texts. I’m sure you’re right. Interpretation of such ancient documents is sure to be full of difficulty. Nonetheless, is the message of the Qur’an any more accessible?
My question therefore is this: why should God have made his final message to the people of the world so unclear that any interpretation at all is needed? If they have any difficulty in understanding...Is it beyond an omnipotent deity to create a message that we can all understand without interpretation? For surely, if the history of Christianity has taught us anything (as you rightly point out), it’s that trouble comes from allowing “experts” to interpret (read: put their own spin on) the word of God for the common people. Are we really to look to what Mohammed’s friends did because God neglected to make it clear enough for us?
Without wishing to sound facetious, it does seem that God has gone out of his way to make an intelligible reading of his last, and presumably most important, message to his creation a bit tricky: not just a language, but an alphabet, that the majority of the world’s population can’t understand, a complicated grammar and a vocabulary strewn with awkward double meanings. Oh, and just to make it more complicated still, the verses are written not in the order that God dictated them but rather in the order of length.
Whilst we’re on the topic of the clarity of the revelation, can you explain to me the concept of abrogation? Once again, I cannot understand why God makes it so difficult for us to take away a clear, unambiguous message from the Qur’an – not to mention how/why an infallible God should need to correct (several times) his final message to mankind and then, in a very human way, tell us to forget the previous verse!“None of Our revelations do We abrogate or cause to be forgotten, but We substitute something better or similar: Knowest thou not that Allah Hath power over all things?” Surah 2: 106“When We substitute one revelation for another, and Allah knows best what He reveals (in stages), they say, “Thou art but a forger”: but most of them understand not.” Surah 16:101
He’s quite right: I understand not.