He (Al-Ghaali) mentions how abrogation enabled extremists to justify their approach (the book is relatively recent, written in 2005).
Dr. Az-Zalmi, author of التبيان لرفع غموض النسخ في القرآن, mentioned a charge against Islam that I never heard before, and the charge uses abrogation to support its premise. Using the claim written many times in classic Muslim literature that the Zakah verse, 9:60, has abrogated all charity verses, the charge alleges that the verse was designed to privilege the rich by not requiring them to do any more charity other than the mandatory Zakah.
The charge is insipid of course because the command to spend is ubiquitous in the Quran and spending is the superset of charity which is a superset of Zakah. The Zakah verse abrogated nothing, it only specified the categories of those deserving of charity. It didn't even say how much each category gets, nor that each must get something. In other words, what the verse really did was prohibit giving charity to other than the eight categories it named. But non-charity mandatory spending is still there, such as a man spending on his wife and children, a widow provided for by her late husband's estate, etc. It's only when the people commanded to spend can't afford it, that's when the government may use collected Zakah to fill those needs and Islamic history is filled with examples of the government helping widows and orphans, for instance, from the Zakah treasury when their guardians could not provide for them.
In his book لا نسخ في القرآن...لماذا؟, page 54, Al-Jabri reports that Abu-Zharr (Al-Ghafaari), may God have been pleased with him, was a staunch advocate for charity that goes beyond the Zakah. One day he and Ka`b Al-Ahbaar were sitting with Calif Uthmaan ibn Affaan, may God have been pleased with him, who asked those present, "What do you say about him who has given alms due on his property, is there any more right in it for others?" Ka`b answered, "No, O Leader of the Faithful." Abu-Zharr pushed Ka`b in his chest and said, "You lie!" And recited,
Then he said, "He mentions the Zakah after
He mentioned giving charity to the needy and others, being good to them and alleviating their needs."
IMHO, Abu-Zharr was right, but not for the reason he gave. The goodness verse, 2:177, speaks of benevolent acts, including mandates, while Uthmaan's question was about rights. The reason Abu-Zharr was right is that Muslims are obligated to support their wives, dependents and their kin. Only when a man cannot afford it does the government step in and support those from the collected Zakah.