Oomis agree with you that the correct pronounciation os probably Sephardic (I am not Sephardic. I reason I agree with you with is general geographics of the times of Matan Torah….
With regards to the last para above why we are in Golus, Phew, I think that is a harsh assumption.
I would like to translate that interpretation as not so much the grammatical pronounciation but the way in which the words are said. Incorrect because they are not said with Kavonoh perhaps? Mispronounced because they are rushed?
Every Yid must question why we are in Golus and correct each of the ways and reasons he feels we do not have Moshiach. Thus, with each Jew correcting his/her ways we are working towards the end of Golus.