Most prophets are social reformers. Muhammad is not an exception. In fact his community was socially in decay and needed reforming. However his main message is about the creator and his worship and the afterlife. Social reformation is a part of the message and is not the sole aim of his message. You can find Jesus message very close to that of Muhammad. But the later have brought the governance into action and the first will let us see it again in his second coming.
1- The one God: a social reformer will not care of religion as much his care about social reforms. He may even try to accept all religions and work through them. But the message of Islam is mainly that of Tawhid God.
14:52 This is a clear message for mankind in order that they may be warned thereby, and that they may know that He is only one god, and that men of understanding may take heed. هَـذَا بَلاَغٌ لِّلنَّاسِ وَلِيُنذَرُواْ بِهِ وَلِيَعْلَمُواْ أَنَّمَا هُوَ إِلَـهٌ وَاحِدٌ وَلِيَذَّكَّرَ أُوْلُواْ الأَلْبَابِ (14:52)
16:22 Your god is one god. But as for those who believe not in the Hereafter their hearts refuse to know, for they are proud. إِلَهُكُمْ إِلَهٌ وَاحِدٌ فَالَّذِينَ لاَ يُؤْمِنُونَ بِالآخِرَةِ قُلُوبُهُم مُّنكِرَةٌ وَهُم مُّسْتَكْبِرُونَ (16:22)
2:133 Or were ye present when death came to Jacob, when he said unto his sons: What will ye worship after me? They said: We shall worship thy god, the god of thy fathers, Abraham and Ishmael and Isaac, one god, and unto Him we have surrendered. أَمْ كُنتُمْ شُهَدَاء إِذْ حَضَرَ يَعْقُوبَ الْمَوْتُ إِذْ قَالَ لِبَنِيهِ مَا تَعْبُدُونَ مِن بَعْدِي قَالُواْ نَعْبُدُ إِلَـهَكَ وَإِلَـهَ آبَائِكَ إِبْرَاهِيمَ وَإِسْمَاعِيلَ وَإِسْحَقَ إِلَـهًا وَاحِدًا وَنَحْنُ لَهُ مُسْلِمُونَ (2:133)
2:163 Your god is one god; there is no god save Him, the Beneficent, the Merciful. وَإِلَـهُكُمْ إِلَهٌ وَاحِدٌ لاَّ إِلَهَ إِلاَّ هُوَ الرَّحْمَنُ الرَّحِيمُ (2:163)
2- He will not challenge the idol worshipers but to win them over: he was about to do that only in one time during the 23 years of his message and God in the Quran warned him.
29:17 Ye serve instead of Allah only idols, and ye only invent a lie. Lo! those whom ye serve instead of Allah own no provision for you. So seek your provision from Allah, and serve Him, and give thanks unto Him, (for) unto Him ye will be brought back. إِنَّمَا تَعْبُدُونَ مِن دُونِ اللَّهِ أَوْثَانًا وَتَخْلُقُونَ إِفْكًا إِنَّ الَّذِينَ تَعْبُدُونَ مِن دُونِ اللَّهِ لَا يَمْلِكُونَ لَكُمْ رِزْقًا فَابْتَغُوا عِندَ اللَّهِ الرِّزْقَ وَاعْبُدُوهُ وَاشْكُرُوا لَهُ إِلَيْهِ تُرْجَعُونَ (29:17)
29:25 He said: Ye have chosen idols instead of Allah. The love between you is only in the life of the world. Then on the Day of Resurrection ye will deny each other and curse each other, and your abode will be the Fire, and ye will have no helpers. وَقَالَ إِنَّمَا اتَّخَذْتُم مِّن دُونِ اللَّهِ أَوْثَانًا مَّوَدَّةَ بَيْنِكُمْ فِي الْحَيَاةِ الدُّنْيَا ثُمَّ يَوْمَ الْقِيَامَةِ يَكْفُرُ بَعْضُكُم بِبَعْضٍ وَيَلْعَنُ بَعْضُكُم بَعْضًا وَمَأْوَاكُمُ النَّارُ وَمَا لَكُم مِّن نَّاصِرِينَ (29:25)
17:73 And they indeed strove hard to beguile thee (Muhammad) away from that wherewith We have inspired thee, that thou shouldst invent other than it against Us; and then would they have accepted thee as a friend. وَإِن كَادُواْ لَيَفْتِنُونَكَ عَنِ الَّذِي أَوْحَيْنَا إِلَيْكَ لِتفْتَرِيَ عَلَيْنَا غَيْرَهُ وَإِذًا لاَّتَّخَذُوكَ خَلِيلاً (17:73)
17:74 And if We had not made thee wholly firm thou mightest almost have inclined unto them a littleوَلَوْلاَ أَن ثَبَّتْنَاكَ لَقَدْ كِدتَّ تَرْكَنُ إِلَيْهِمْ شَيْئًا قَلِيلاً (17:74)
17:75 Then had We made thee taste a double (punishment) of living and a double (punishment) of dying, then hadst thou found no helper against Us. إِذاً لَّأَذَقْنَاكَ ضِعْفَ الْحَيَاةِ وَضِعْفَ الْمَمَاتِ ثُمَّ لاَ تَجِدُ لَكَ عَلَيْنَا نَصِيرًا (17:75)
3- Sin is forgivable and actually all, except taking partner with him: a social reformer would be against sins since they are destructive to communities. God and faith in him come first before sins, which are forgivable.
39:53 Say: My slaves who have been prodigal to their own hurt! Despair not of the mercy of allah, Who forgiveth all sins. Lo! He is the Forgiving, the Merciful.
قُلْ يَا عِبَادِيَ الَّذِينَ أَسْرَفُوا عَلَى أَنفُسِهِمْ لَا تَقْنَطُوا مِن رَّحْمَةِ اللَّهِ إِنَّ اللَّهَ يَغْفِرُ الذُّنُوبَ جَمِيعًا إِنَّهُ هُوَ الْغَفُورُ الرَّحِيمُ (39:53)
4- He did mention to the Jews the critic of God when they were disobedient: a social reformer will mind his business and will not get into these. The Quran as well tell them about most they differ in.
27:76 Lo! this Qur'an narrateth unto the Children of Israel most of that concerning which they differإِنَّ هَذَا الْقُرْآنَ يَقُصُّ عَلَى بَنِي إِسْرَائِيلَ أَكْثَرَ الَّذِي هُمْ فِيهِ يَخْتَلِفُونَ (27:76)
5- The Quran explicitly talked about 25 prophets: a social reformer would not care much of going through all these stories.
11:100 These are some of the stories of communities which We relate unto thee: of them some are standing, and some have been mown down (by the sickle of time). ذَلِكَ مِنْ أَنبَاء الْقُرَى نَقُصُّهُ عَلَيْكَ مِنْهَا قَآئِمٌ وَحَصِيدٌ (11:100)
11:120 All that we relate to thee of the stories of the apostles,- with it We make firm thy heart: in them there cometh to thee the Truth, as well as an exhortation and a message of remembrance to those who believe. وَكُـلاًّ نَّقُصُّ عَلَيْكَ مِنْ أَنبَاء الرُّسُلِ مَا نُثَبِّتُ بِهِ فُؤَادَكَ وَجَاءكَ فِي هَـذِهِ الْحَقُّ وَمَوْعِظَةٌ وَذِكْرَى لِلْمُؤْمِنِينَ (11:120)
12:3 We do relate unto thee the most beautiful of stories, in that We reveal to thee this (portion of the) Qur'an: before this, thou too was among those who knew it not. نَحْنُ نَقُصُّ عَلَيْكَ أَحْسَنَ الْقَصَصِ بِمَا أَوْحَيْنَا إِلَيْكَ هَـذَا الْقُرْآنَ وَإِن كُنتَ مِن قَبْلِهِ لَمِنَ الْغَافِلِينَ (12:3)
6- The Quran criticized the Christians for worshiping Jesus: a social reformer would not get in the middle between them and their religion. He would not create more enemies, if anything he would like to win them over.18:4 And to warn those who say: Allah hath chosen a son, وَيُنذِرَ الَّذِينَ قَالُوا اتَّخَذَ اللَّهُ وَلَدًا (18:4)
18:5 (A thing) whereof they have no knowledge, nor (had) thee fathers. Dreadful is the word that cometh out of their mouths. They speak naught but a lie. مَّا لَهُم بِهِ مِنْ عِلْمٍ وَلَا لِآبَائِهِمْ كَبُرَتْ كَلِمَةً تَخْرُجُ مِنْ أَفْوَاهِهِمْ إِن يَقُولُونَ إِلَّا كَذِبًا (18:5)
7- Too much devotion to God: all the Quran is about God and not Muhammad. Muhammad life is all about obeying God and living by the commands of God in the Quran. He was asked to pray more than us and he did that and more he was fasting and praising God more than us.
76:26 And worship Him (a portion) of the night. And glorify Him through the livelong night
وَمِنَ اللَّيْلِ فَاسْجُدْ لَهُ وَسَبِّحْهُ لَيْلًا طَوِيلًا (76:26)
73:20 Thy Lord doth know that thou standest forth (to prayer) nigh two-thirds of the night, or half the night, or a third of the night, and so doth a party of those with thee. But Allah doth appoint night and day in due measure He knoweth that ye are unable to keep count thereof. So He hath turned to you (in mercy); read ye, therefore, of the Qur'an as much as may be easy for you. He knoweth that there may be (some) among you in ill-health; others travelling through the land, seeking of Allah's bounty; yet others fighting in Allah's Cause, read ye, therefore, as much of the Qur'an as may be easy (for you); and establish regular Prayer and give regular Charity; and loan to Allah a Beautiful Loan. And whatever good ye send forth for your souls ye shall find it in Allah's Presence,- yea, better and greater, in Reward and seek ye the Grace of Allah, for Allah is Oft-Forgiving, Most Merciful. إِنَّ رَبَّكَ يَعْلَمُ أَنَّكَ تَقُومُ أَدْنَى مِن ثُلُثَيِ اللَّيْلِ وَنِصْفَهُ وَثُلُثَهُ وَطَائِفَةٌ مِّنَ الَّذِينَ مَعَكَ وَاللَّهُ يُقَدِّرُ اللَّيْلَ وَالنَّهَارَ عَلِمَ أَن لَّن تُحْصُوهُ فَتَابَ عَلَيْكُمْ فَاقْرَؤُوا مَا تَيَسَّرَ مِنَ الْقُرْآنِ عَلِمَ أَن سَيَكُونُ مِنكُم مَّرْضَى وَآخَرُونَ يَضْرِبُونَ فِي الْأَرْضِ يَبْتَغُونَ مِن فَضْلِ اللَّهِ وَآخَرُونَ يُقَاتِلُونَ فِي سَبِيلِ اللَّهِ فَاقْرَؤُوا مَا تَيَسَّرَ مِنْهُ وَأَقِيمُوا الصَّلَاةَ وَآتُوا الزَّكَاةَ وَأَقْرِضُوا اللَّهَ قَرْضًا حَسَنًا وَمَا تُقَدِّمُوا لِأَنفُسِكُم مِّنْ خَيْرٍ تَجِدُوهُ عِندَ اللَّهِ هُوَ خَيْرًا وَأَعْظَمَ أَجْرًا وَاسْتَغْفِرُوا اللَّهَ إِنَّ اللَّهَ غَفُورٌ رَّحِيمٌ (73:20)
8- Polygamy of the prophet: which commonly some people are using against him. For Muslims it is actually a proof of prophethood. Since he was not involved with another woman until his marriage at 25 years old of a woman of 40 years old. He did not marry after she died for few years and started to marry again at about 52 years old. At a time when he was very busy with spreading Islam and having enemies everywhere from disbelievers, hypocrites and some of the people of the book. A social reformer may not marry or will just marry again after his wife death one woman and keep low profile with the family life so he can take care of his social reforms.
33:38 There is no reproach for the Prophet in that which Allah maketh his due. That was Allah's way with those who passed away of old and the commandment of Allah is certain destiny. -
مَّا كَانَ عَلَى النَّبِيِّ مِنْ حَرَجٍ فِيمَا فَرَضَ اللَّهُ لَهُ سُنَّةَ اللَّهِ فِي الَّذِينَ خَلَوْا مِن قَبْلُ وَكَانَ أَمْرُ اللَّهِ قَدَرًا مَّقْدُورًا (33:38)
33:39 Who delivered the messages of Allah and feared Him, and feared none save Allah. Allah keepeth good account. الَّذِينَ يُبَلِّغُونَ رِسَالَاتِ اللَّهِ وَيَخْشَوْنَهُ وَلَا يَخْشَوْنَ أَحَدًا إِلَّا اللَّهَ وَكَفَى بِاللَّهِ حَسِيبًا (33:39)