^
Even if our Sunni scholars make mistakes in recitation, this is not such a big issue in comparison to the Shia Marja's, because each one of the Marja's supposes himself as a type of Mujtahid Mutlaq like Imam Maalik or Imam Ash-Shafii, who can deduce rulings directly from the sources given his huge knowledge. But how can one deduce something if he cannot get past one line of the Quran without making all these mistakes?
Mind you, in the case of such a Mujtahid, his verbal recitation is authoritative even beyond the text [since the text has to be taught to be read by a teacher] but again: It seems these Marja's are simply unable to pronounce Arabic letters properly no matter what they try (unless if they have some proof that Arabic should actually be pronounced like this, which I believe will be difficult to present). What we would do is write down what they say, and try to see if it can be reconciled to anything we can call Quran.
So I say, this angle should not be left alone, it is a major issue of how such Ayatullahs would be trusted with carrying the religion and directly deducing the rulings of the religion, since their claims are above and beyond what any Sunni scholar makes today anyway.