First, many claim that the name should not be used because the original way to pronounce it is unknown today. Ancient Hebrew was written without vowels. Therefore, no one today can say for sure exactly how people of Bible times pronounced YHWH. However, should this prevent us from using God’s name? In Bible times, the name Jesus may have been pronounced Yeshua or possibly Yehoshua—no one can say for certain. Yet, people the world over today use different forms of the name Jesus, pronouncing it in the way that is common in their language. They do not hesitate to use the name just because they do not know its first-century pronunciation. Similarly, if you were to travel to a foreign land, you might well find that your own name sounds quite different in another tongue. Hence, uncertainty about the ancient pronunciation of God’s name is no reason for not using it.
The problem here is twofold. The correct name to call God and its use in the Christian Greek Scriptures (or NT).
With regards the first point, the correct name to call God, if it doesn't matter what name to call God then surely God isn't fussed about the name that he is called?
Which means LORD is perfectly acceptable.
The WT argument seems to be that LORD doesn't sound very personal. But no one knows how to pronounce YWHW because God hasn't told anyone. So surely that means God isn't fussed about the name that he is called? This argument gets very circular!
The real problem is the Christian Greek Scriptures (or NT). YHWH never occurs in it. There is an excellent book by Professor Jason BeDuhn called 'Truth in Translation: Accuracy and Bias in English Translations of the New Testament'. In it he's clearly a big fan of the Watchtower's translation of the Bible. But...he devotes the entire appendix to destroying the WT's addition of Jehovah to the Christian Greek Scriptures. Which is what the vast majority of Bible scholars state. It's a fiction. They have changed the Bible to add this.
So YHWH only occurs in the Hebrew scriptures and no one actually knows how to pronounce it - so there is no reason not to use LORD.
YHWH never occurs in the the Christian Greek Scriptures - it's an addition by the WT in their translation.