Why use 'God' or 'Lord' when those aren't names?
This stems from a Jewish reticence to avoid risking speaking the Lord's name in vain, whereby only the High Priest would pronounce it in the Sanctum Sanctorum on the Day of Atonement. The custom was and still is to read "Adonai" meaning "Lord" in place of it in the Synagogue and thus the KJV and most other English translations of the Hebrew follow suit.
At that, contemporary Orthodox Jews try to avoid saying or writing the word God, so if you visit a Jewish website you will find Hashem, meaning The Name, or the abbreviation G-d, used extensively. G-d of course has the unfortunate connotation of referring to a blasphemous damnatory utterance in ordinary English.
Now, within Christianity we do of course routinely refer to God by name (Jesus Christ).
No. Jesus Christ is the name for God the Son, the incarnate Logos, the Second Person of the Trinity. Who is "Very God of Very God."
The name for God in the OT is specifically YHWH.
Indeed, however, Jesus Christ is a person of the Trinity and is properly God in the same sense that the Father and Holy Spirit are God.
Obviously my position reflects Nicene Orthodoxy; I am not a heretic.
This would mean the name for God, YHWH, isn't Jesus then, wouldn't it?
No, because according to the Council of Ephesus it is essentially heretical to refuse to ascribe to the person of Christ the full divine dignity. So one can call God Jesus Christ; it would be incorrect only if one was referring to all three persons or to a person of the Trinity other than Jesus Christ, which would imply the confused heresy of Sabellius recently revived by the moronic Oneness Pentecostals. However, to refuse to call Jesus Christ God, for example, by rejecting the term Theotokos to refer to St. Mary, one instead engages in Nestorianism or potentially Arianism or another heresy relating to Triadology.
If YHWH isn't identifying Jesus, who is it identifying?
I think the Tetragrammaton could hypothetically be used to refer to the Trinity in the abstract. I am disinclined however to support the active use of it in contexts where it is not presently used by Orthodox Christians.
Which I in fact addressed in my initial response.
The name for God in the OT is specifically YHWH.
Just please give us the verse that states we are only to call Him YHWH---and explain why, when Moses asked who shall I say sent me:
(Exo 3:13) And Moses said unto God, Behold, when I come unto the children of Israel, and shall say unto them, The God of your fathers hath sent me unto you; and they shall say to me, What is his name? what shall I say unto them?
(Exo 3:14) And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you.
(Exo 3:15) And God said moreover unto Moses, Thus shalt thou say unto the children of Israel, The LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations.
Well as I said I think in the lack of clear context the name should be properly applied to God or the Trinity in the abstract as an unified entity.
Jesus's name means YHVH's Salvation, Since God hears what's in our hearts louder than our lips, I say it all the time.