One of many boastings from KJVOnlyists is that the KJV, allegedly, is the clearest Bible on a number of issues. Most commonly, they claim modern translations have removed the Deity of Christ (an obvious no-no), and at least as far as the NIV goes, less clearly opposed to homosexuality.
The latter claim is especially amusing to me, given that I was persuaded to repent of my own homosexual lifestyle very early on into my faith, while my primary (and really only) study version was the NIV. If the NIV is so unclear on homosexuality, it wouldn't have been able to convince me that the lifestyle I really wanted to keep, the desires that I felt were integral to my identity, were actually offensive to God. When KJVOnlyists use this particular line of reasoning on me, I just have to laugh, because they are talking to absolute proof that they are wrong; it is the heart of the believer, not the translation, that inclines people towards heretical views.
But the Deity of Christ thing is also an obvious no-no. Indeed, there are modern "translations" specifically designed to remove it. The New World Translation, produced by the anti-Trinitarian cult of the Jehovah's Witnesses, for example, is disqualified as a translation because it is biased against a clear doctrine, intentionally mistranslating texts such as John 1:1 with the intention of removing the obvious deity of Christ from it.
Now, it's interesting to note is that even a bad translation is still usable. Not in the sense that I'd happily hand out NWTs to new converts as a primary study Bible. No, if someone asked for a Bible, and the NWT was all I had to hand, I'd simply say "I don't have one". Nevertheless, because God is so wise, only a brilliant theologian would be able to corrupt it to such an extent that the Trinity is removed. A bad theologian would only think to remove explicit statements, such as "...the word was God...". But the Trinity is more than just explicit statements. It is also clear from the fact statements which can only be applied to God are applied to Jesus. Take, for example, a comparison of Psalm 89:6 with Hebrews 1:3. The NWT is not so corrupt as to fail to show that while no one among the sons of God are like God, Jesus is "the exact representation of His very being". Thus, using the admittedly corrupt NWT, we can show our JW rescue targets the following syllogism:
P1: No one but God is like God.
P2: Jesus is like God.
C: Jesus is no one but God.
But that's not saying corrupt translations are acceptable. I can agree with KJVOnlyists on this: We should absolutely be committed to ensuring we use the most faithful translations possible. If the KJV truly was the only faithful translation, and all others truly were corrupt, I would go back to being KJVOnly. Nevertheless, this is demonstrably not the case.
See, the measure of a good translation is not "how well does it present the Deity of Christ", but "how well does it represent the original text?" Think of it this way: In the KJV, John 1:1 reads "In the beginning was the Word, and the Word was with God, and the Word was God." It is easy to make this verse more clearly Trinitarian by translating it "In the beginning was the word, Jesus Christ, and Jesus Christ the word was with God, and Jesus Christ was God, for God is a Trinity, and Christ is divine". Notice, while I have made the Deity of Christ more clear, and have not even said anything remotely false, I am no longer faithfully translating the Bible. Instead, ironically, I am translating my own bias into the text. It may be a good bias, but it is a bad translation.
That being said, just as we can show the Deity of Christ even from a legitimately bad and biased translation, we can show true Christian doctrines from any half way decent translation. In fact, the greatest irony of this whole debate is that every reputable translation gives the identical picture of Christianity to the KJV. In fact, 9 times out of 10, the only discernible difference between a KJVOnlyist and any other faithful Christian will be KJVOnlyism. The exceptions are never traceable to translation preferences. Nevertheless, if one was sneaky enough, one could try.
The easiest example for me as a Creation apologist is the grotesque misuse of Genesis 1:28. In the KJV, this reads "And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth." (Emphasis added). That word "replenish" is an accurate translation, or at least it was for 1611. Back then, it simply meant "fill"; the prefix "re" did not mean "again". Yet, to compromisers like Hugh Ross, the word is accurate even today. This translation is used to support the so-called ruin-reconstruction theory, in which God chose Adam and Eve to replenish the earth following the destruction of a pre-Adamic race.
No matter which translation you read, this theory is complete balderdash. It is not a theory based on the text, nor on any evidence at all. When Old Earthers capitalise on the word "replenish", they are doing so retroactively, coming to a conclusion, then seeking textual support for it, rather than studying the text and drawing a conclusion from it. Much like KJVOnlyists do when they conclude KJVOnlyism, then throw Titus 3:10 at you to say you're not Christian if you use other translations.
Nevertheless, this "problem" would go away completely if Old Earth compromisers had not read the KJV. I can assure you, they did not come to their conclusion that replenish is the right word based on studying the Hebrew. Hugh Ross was even once trapped by a Hebrew speaker, who asked him "do you speak Hebrew?" in Hebrew, and asked him to respond in Hebrew. He couldn't. No, their argument is based almost exclusively on the KJV. By contrast, the dreaded NIV says "God blessed them and said to them, “Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.”" Boom, no ruin-reconstruction theory, and it even has correct modern English punctuation.
Far more common than creation compromise is the so-called Prosperity Gospel. This heretical view states that, in stark contrast to the endless warnings that we will have trouble on this earth, God wants us to be permanently happy, healthy, and wealthy, and so an increase of faith will bring an increase in prosperity. The most cliched verse cited in its defence is, of course, Philippians 4:13, which, in the KJV, says "I can do all things through Christ which strengtheneth me." So obviously, all we need to do is pray, and we can win that sporting event, get into that college, earn that promotion, and become a millionaire, right?
In context, no. And again, you don't need to leave the KJV to prove this, it's in the previous verses. But the NIV renders this verse "I can do all this through him who gives me strength." In other words "hey, guys, there's extra context to this, don't send all your money to this con artist based on one misquoted verse, read the rest of what I said and you'll see I'm talking about enduring hardships like poverty and imprisonment, not about avoiding them completely". The NIV, in this one case, is clearer than the KJV, which can be far more easily exploited by prosperity preachers.
What's especially of note is that even when it comes to the Deity of Christ, there are places where the NIV is clearer than the KJV. Titus 2:13, for example. In the NIV, we are told of the glory of "our Great God and Savior, Jesus Christ". This clearly refers to only one person, showing that Jesus Christ is God. However, in the KJV, we read "the Great God and our Saviour Jesus Christ". In the NIV, the punctuation alone links "our Great God and Savior" as one being, whereas in the KJV, which of course lacks modern punctuation, one could easily say "the Great God is one person, and our Saviour Jesus Christ is another". Not that this is in any way justified. Those who deny the Deity of Christ are Hell-bound heretics, and this can be proven from any translation. Nevertheless, they will always try to show otherwise, and it is easier, at least in this case, for them to do so with the KJV.
Now, at the end of the day, absolutely none of this matters. All reputable translations, including the KJV, teach the same doctrines as the original text, simply because they are translations of it. The clarity of those doctrines is irrelevant, what matters is faithfulness to the original text, and all reputable translations are. In fact, differences between the KJV and other translations, even the NIV, are often as trivial as synonymous words, swapped words (e.g. "Christ Jesus" and "Jesus Christ"), or words that have changed meaning since 1611. None of these differences make any translation any less the word of God, none of them give a different Christian faith, none of them make one any less Christian by believing them. Therefore, the KJVOnly debate is an unnecessarily divisive one, and you know what the Bible says about petty quarrels and divisive people. "Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them." (Romans 16:17, KJV)