1. Muslims generally view translating the Qur'an as sacrilege. I'm sure they wouldn't appreciate a bunch of Christians translating it into every language for them.
2. The reed sea/ red sea thing isn't a matter of mistranslation. It's a matter of genuine debate. There are multiple different valid translations, and multiple potential crossing sites... that we know of. Since it was written approximately 3000 years ago, that can make things difficult in figuring out some of the
3. There are 48 surviving copies. It is unknown how many were printed. A low estimate is around 150. So, that makes 150 copies of a book, all of which are EXACTLY THE SAME, and took only a few years work by a single person, including type setting... At a time when it would take a single person several years to transcribe ONE COPY, and every copy was unique. As the first major book printed this way, bet your sweet ass it was a revolution.
4. You're right, Gutenberg did not translate the bible. No one has claimed that. But the King James bible was significantly later, and make possible by the Gutenberg bible. The comparison make it the article is an excellent one.