Maybe I was wrong in saying it “declares it perfect”, but the Quran declares itself as “sent in Arabic, clear and free from crookedness” or in “a clear Arabic tongue”. Scholars (from Ahl Al Salaf, so they have more authority) often interpreted that as God deliberately choosing Arabic to communicate his message as Arabic was the best language that God chose to communicate his final message in its clearest form to humans. There are further sayings by the prophet that reciting the Quran and prayers in full proper Arabic has a special place to God.
There were modest attempts at reform and improvements, but they were never titled as “improvements” or “modernization” especially that the latter is a word with negative connotations in Islam, but rather as something more pragmatic or logistical like the adoption of new words, or dropping some complex rule or style.
There is indeed a great diversity in Arabic, but there is 1 “correct” Arabic which is the Quranic/Classical Arabic. Egyptian, Levantine, Hejazi, and Maghrabie are only some of the main variations on Arabic, but all those speakers would agree that it’s not the “correct” Arabic. Reciting the Quran or quoting the prophet in such dialect would be extremely disrespectful. Most religious authorities might speak in that dialect to help with communication, then revert to Classical Arabic when quoting either of those.
The most “moderination” Classical Arabic got was Modern Standard Arabic (MSA) which was really about accepting some simplified grammar and prose in professional writing rather than introducing anything completely novel or new. It made it acceptable to write books or articles in simpler prose rather than requiring or expecting the extremely elaborate writing style of true Classical Arabic. Most importantly, it didn’t forbid or declare anything from Classical Arabic “outdated” or “wrong” but rather just saying “it’s a bit too much, maybe”
The resistance to modify the typography is definitely there, but I wasn’t saying that it will necessarily succeed in preventing the modification. The Quran in its 7th century form will have to remain the authority on Arabic, followed by all the writings and literature of the following centuries. However you can find the Quran written phonetically in “Academic Romanization” format as Muslim view it more of a translation of sorts, rather than an actual reproduction of the Quran. I don’t know of any “Arabiz” versions of the Quran, and I suspect it would be viewed as disrespectful by many, but I won’t be surprised if some were on the internet or would appear in print at some point.
FWIW, I don’t think many (of the reasonable people) would oppose the changes proposed by this typography changes, but I suspect that most would either view it as strange or unnecessary because at the end of the day it just looks like a broken font more than anything.
Edit: Theology gets complicated but The Mu'tazilite split in the 9-10th century was mainly about the true nature of the Quran. They argued that it was a created vs being an eternal attribute of God. They lost the debate in the Muslim world and the opinion that won was that the Quran was the literate word of God that is eternal and wasn't created but always existed. The debate wasn't about language, but language (being the medium of the Quran) was part of it where Mu'tazilite had to try to define the difference between expression, and linguistic limitations in communication. They lost the debate and their influence weaned in general though left remnants in post-prophet history of Islam.