Was the Noble Qur’an written in one dialect, and is that considered a deficiency or shortcoming?

The Companions, during the era of Uthman, compiled the Quran according to the dialect of Quraish. Uthman commanded Zayd ibn Thabit and three men from Quraish to transcribe the scrolls into codices. He instructed them that if they disagreed on anything, they should write it in the dialect of Quraish. Then, Uthman sent a copy of the codex to every region. The Companions intentionally left the codices devoid of diacritics (ضبط) to accommodate the authenticated readings (qira'at). Some extra words found in specific readings were written in certain codices. This diversity is not considered a defect in the Quran, because it is the preserved word of Allah, as stated in His saying: "Indeed, it is We who sent down the Dhikr (definition) (the Quran), and indeed, We will be its guardian" (15:9). Rather, it is considered part of the perfection of the Quran.