Jehovah is the earliest transliteration of the Divine Name in English.
That it was the earliest transliteration of the divine name, doesn't make it in any sense correct. Lots of things when transliterated into another alphabetical system can go wrong.
If you look at what the Gnostics tried, they came up with, amongst other things, IAO, understandable because the Greeks didn't do too well with the /h/ sound (the "he" in Hebrew). Note two things from this, 1) nothing to support the English pronounced "j", but rather the "y", and 2) the vowel after the "I" being an "A". The "O" is a transliteration for the Hebrew letter "waw". So, let's re-insert the /h/s into the transliteration and we get YaHWH.
The "j" of "Jehovah" is simply a problem of passing from one orthography to another without compensating. It obviously should be "y". The "v" is another simple problem: it doesn't represent the sound in the original, but the way the sound changed from Hebrew into German influenced Yiddish.
Having been around for a long time is no argument for justifying the obviously mistaken English form Jehovah. Amongst other things the second vowel is not justified by Hebrew morphology. Why is the middle vowel there at all? It's unexpected from the Hebrew original. "Jehovah" is just a series of mistakes.
English speakers are not renowned for their linguistic ability. This is how we ended up with some awful forms from other languages: Peking, Ceylon, Munich, the Poonjab (as they pronounced it), etc. One normally corrects the errors of the past.
But why is there a debate over the pronunciation of the name of God, when those in whose culture the name appeared, long ago stopped pronouncing it, as it was too sacred to say? The Jews, as you know, referred to their god as ha-Shem ("the name") and everyone who adhered to the religion knew exactly what was meant. In ancient manuscripts it was written in Palaeo-Hebrew script to set it apart from the other words, to warn the reader not to pronounce it.
The traditional substitution when the Hebrew bible was translated was
kurios ("lord") in Greek,
dominus ("lord") in Latin, and of course "Lord" in English. Substitution has been the tradition since the second temple period. "Jehovah" is an aberration from that tradition, which doesn't even reflect the original orthographic representation of the name in Hebrew. It does reflect English difficulties in the field of linguistics.
The form "Yahweh" is supported by the gnostic evidence; it doesn't make any deviant substitutions for letters in the original consonantal form; and has a much better chance of reflecting a hypothetical original pronunciation.