It is unlikely that the reason why people have switched to more modern translations is "because they don't like something that the Lord spoke to them out of the KJV". Much more likely that they don't understand the antiquated language of the KJV--it doesn't say much at all to them. The dense theological concepts of Paul are much easier to understand in a more modern translation. It has been my experience that those who have "itching ears" and won't "endure sound doctrine"
really don't read the Bible in any version.
I repeatedly check one version against another (yes--the KJV also) and there is very little difference between versions--certainly none that substantially alter the meaning. Now this wouldn't be true of Eugene Peterson's
The Message --which I consider to be a paraphrase, and
The Message does substantially alter the meaning. I don't care for any of the NIV editions beyond 1975 either, but if that was all I had, I would read it.
There is enough duplication in all of the actual translations (as opposed to paraphrases) that it would be extremely difficult to miss the proper gospel message, from the point of the actual words. Error mostly comes from improper interpretation, not from poor translation. The Holy Spirit guides into all truth--not men. An example of the duplication of thought would be the "mini-gospel" of 1 Corinthians chapter 15. Following the "love chapter" (chapter 13) it tells you how to conduct yourself as a Christian and be "perfected in love" of which John Wesley often spoke.
The Book of Romans is a primer on being a Christian as well--along with some fairly heavy theological concepts. Wesley said that he was converted upon hearing Luther's preface to the Book of Romans. Wesley is often accused of preaching that "entire sanctification" is possible in this life but that is not true. One point of confusion is that the Greek word
teleioi found in Matthew 5:48.
Teleioi does not mean "flawless" or "spotless" but rather, "complete". Thus, Wesley taught that a Christian becomes
complete in love (NOT perfectly sinless).
https://www.theopedia.com/wesleyan-perfectionism We often speak of being of a "mature" faith in the same way. It is clear that Wesley was not sinless in his own life. He and his wife, Mary, had a terrible marriage--she left him after only seven years. Mary was independently wealthy--and lived apart from John for the rest of her life. She told friends that she left John because she found a packet of "love letters" (in a secret drawer in his wardrobe chest) which he wrote to a woman who had been with him in ministry (she had apparently returned them upon her marriage to another man). John didn't even attend Mary's funeral when she died. Earlier, about her, he said somewhat sarcastically: "I did not forsake her, I did not dismiss her, I will not recall her."
Others who came after Wesley, began to preach that "entire sanctification" was possible in this life. It is linked to the concept of
theosis --that it is possible to merge with God and be perfect in holiness before death (the pagan mystics had long held such beliefs). Most all students of the Bible (at least in Western Christianity) consider the notion to be mystical and at odds with gospel truth. They have thus called the concept of possible moral perfection in mortality to be heresy, and I agree that the Bible does not teach any such thing.