Well, let me point you to two places where the KJV simply got it wrong.
Psalm 121:1, "I to the hills will lift mine eyes, from whence doth come mine aid" is a question, not a statement. Here KJV follows Latin Vulgate along with Luther and the Geneva Bible, rather than working with the Hebrew text. me'ayin is always a question, everywhere else it occurs in the OT ("from whence?").
Likewise in the last word of Proverbs 29:18a "Where there is no vision the people perish", the KJV likewise follows the Vulgate (dissipabitur = destroyed; Geneva Bible: "decay") in its translation of the Niphal of para', which actually means "to unbind (hair), to let loose, run unrestrained). Hence Luther's accurate and vivid "das Volk wird Wild und Wust". I can find no other ancient or modern translation that agrees with KJV in English, French, German, Dutch, Spanish or Italian (I'd be happy to be corrected, if I missed something). And while we're at it, hazon, vision, specifically means a prophetic vision, not a generic "vision for evangelism" or similar modern parlance. That's not directly the KJV's fault, but it does make the ESV's translation "Where there is no prophetic vision, the people cast off restraint" significantly clearer.
As far as your anecdotal knowledge of current standards of Greek tuition, your experience is your experience. I'm sorry for those who have had bad experiences. Perhaps you should advise your friends to study at Westminster, where it is taught more adequately. And there is no direct correlation between the average seminary Greek student and the competence of those who engage in the Bible translation process.