1. It is inherently discriminatory and oppresive; it does not treat all people alike, its does not even treat all Muslim alike; for example, women are not treated with equality, non-Muslims are not treated with equality with Muslims. How can that be regarded as good?
Men and women are not the same nor are they "equal" as some folks would have us believe. Whatever is on one side of an 'equals' sign must be exactly the same as what is on the other side without any difference in value, only in the way that it is expressed. How then could we say that a man, who is unable to conceive or give birth and then breast feed a baby is the equal to a woman who can?
They are equal in their beliefs and good deeds of course. But still they are not the same as each other. Each one must fulfill their role as humans.
Praise be to Allaah.
Firstly:
This word – equality – which many thinkers in both the east and the west advocate in various fields of life is a word which is based on deviation and a lack of understanding, especially when the speaker attributes this idea of equality to the Qur’aan and to Islam.
One of the things that people misunderstand is when they say that “Islam is the religion of equality”. What they should say is that Islam is the religion of justice.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said:
“Here we should note that there are some people who speak of equality instead of justice, and this is a mistake. We should not say equality, because equality implies no differentiation between the two. Because of this unjust call for equality, they started to ask, what is the difference between male and female?’ So they made males and females the same, and then the communists said, ‘What difference is there between ruler and subject? No one has any authority over anyone else, not even fathers and sons; the father has no authority over his son,’ and so on.
But if we say justice, which means giving each one that to which he or she is entitled, this misunderstanding no longer applies, and the word used is correct. Hence it does not say in the Qur’aan that Allaah enjoins equality, rather it says (interpretation of the meaning):
“Verily, Allaah enjoins Al‑‘Adl (i.e. justice)”
[al-Nahl 16:90]
“and that when you judge between men, you judge with justice”
[al-Nisa’ 4:58]
Those who say that Islam is the religion of equality are lying against Islam. Rather Islam is the religion of justice which means treating equally those who are equal and differentiating between those who are different.
No one who knows the religion of Islam would say that it is the religion of equality. Rather what shows you that this principle is false is the fact that most of what is mentioned in the Qur’aan denies equality, as in the following verses:
‘Say: Are those who know equal to those who know not?”
[al-Zumar 39:9]
‘Say: Is the blind equal to the one who sees? Or darkness equal to light?’
[al-Ra’d 13:16]
‘Not equal among you are those who spent and fought before the conquering (of Makkah, with those among you who did so later’
[al-Hadeed 57:10]
‘Not equal are those of the believers who sit (at home), except those who are disabled (by injury or are blind or lame), and those who strive hard and fight in the Cause of Allaah with their wealth and their live’
[al-Nisa’ 4:95]
Not one single letter in the Qur’aan enjoins equality, rather it enjoins justice. You will also find that the word justice is acceptable to people, for I feel that if I am better than this man in terms of knowledge, or wealth, or piety, or in doing good, I would not like for him to be equal to me.
Every man knows that he find it unacceptable if we say that the male is equal to the female.”
Sharh al-‘Aqeedah al-Waasitah, 1/180-181
Based on this, Islam does not regard men and women as equal in matters where regarding them as equal would result in injustice to one of them, because equality that is inappropriate is a severe form of injustice.
The Qur’aan commands women to wear clothes that are different from those worn by men, because of the differences in the ways each sex is tempted by the other. The temptation posed by men is less than the temptation posed by women, so the clothes that women should wear are different than the clothes that men wear. It makes no sense to tell women to expose the parts of the body that men are allowed to expose, because of the differences in the temptation posed by a woman’s body and a man’s body – as we shall explain.
http://islamqa.com/en/ref/1105/equal
take a min to read it.
2. It has I am told many outdated laws on land and property that could not possibly have any validity in a modern society.
Like what

cant help if i dont know what you are talking about pls show us
3. It has a huge section on slavery and I find it impossible to belive that most or any Muslim would want that imposed on any society?
Praise be to Allaah.
Discussing slavery and asking questions about it on the part of those who promote Christianity and try to divert people from following the religion of Islam is something that annoys the wise person and makes him point the finger of accusation towards the ulterior motives that lie behind these questions.
That is because slavery is well established in Judaism and Christianity, where it has taken unjust forms. They have many books which discuss that in detail and condone it. Therefore it makes you wonder: how can these churchmen call people to Christianity when Christianity condones and legitimizes slavery?
In other words: how can they stir up an issue when they themselves are up to their necks in it?!
The issue of slavery is completely different when discussed from the angles of Christianity and Islam, and when compared with the situation that prevailed at the advent of Islam.
Hence we must discuss this topic in some detail with reference to what is said in Judaism, Christianity and contemporary culture on this matter, then we will speak of slavery in Islam.
Many lies have been fabricated about Islam on this topic, at a time when criminals with lengthy track records are safe and nobody points a finger at them.

PLS read the rest here to understand Islam and slavery ...
http://islamqa.com/en/ref/94840/slavery
4. One final example, music is regaded as forbidden in Islam but according to Nawawi's manual; of Islam killing with a good reason is acceptable.
Praise be to Allaah.
Killing a non-Muslim when he is a mu’aahid (one of those who have a peace treaty with the Muslims) is a sin, one of the major sins. Al-Bukhaari narrated that ‘Abd-Allaah ibn ‘Amr ibn al-‘Aas (may Allaah be pleased with them both) said: “The Prophet (peace and blessings of Allaah be upon him) said: ‘Whoever kills a mu’aahid will not smell the fragrance of Paradise, even though its fragrance may detected from a distance of forty days.’” But with regard to non-Muslims who are at war with the Muslims and do not have a peace treaty with the Muslims or are not living under Muslim rule, then Muslims are commanded to kill them, because Allaah says (interpretation of the meaning):
“Fight those of the disbelievers who are close to you, and let them find harshness in you” [al-Tawbah 9:123]
But this should be in the case of jihaad under the leadership of one of the leaders of the Muslims, or his deputy.
Shaykh ‘Abd al-Kareem al-Khudayr
Many people will say different things, But when looked at in context and with full knowledge, we can see that the Quran allows killing in self defence, but sets clear limits. God encourages muslims to fight to defend themselves from oppression, but warns them not to trangress limits that he has set
Prophet (may peace be upon him) Said "Stop, O people, that I may give you ten rules for your guidance in the battlefield. Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman. nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy's flock. save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone"
If any one slew a person - unless it be for murder or for spreading mischief in the land - it would be as if he slew the whole people - Quran 5:32
And in a hadith narrated by Abdullah bin Amr bin Al-As, God Told Mohammed :
You are neither hard-hearted nor of fierce character, nor one who shouts in the markets. You do not return evil for evil, but excuse and forgive. - Bukhari, Volume 6, Book 60, Number 362
Fight in the cause of Allah those who fight you, but do not transgress limits; for Allah loveth not transgressors. - Quran 2:190