Peter knew that Jesus was the Christ, the son of the living God (the Son and heir of God), and rightly called Him Lord, but it wasn't revealed to him by 'flesh & blood' - it was put to his heart.
You can't expect JWs to simply think Jesus is God. It doesn't fit with the rest of the doctrines, and I don't think it can really. All the other stuff has to change too, like earning salvation or truly trusting the Lord, not to 'keep His word', but trust as the truest type of friend. Maybe some can't get that with all that gestapo antideemin activity going on - I dunno.
JWs see God as an 'other', and this is also evident in marriage, where God blesses from an 'other' position. But christian marriage is of three, includes God, as it was in the beginning where the Lord was in the garden too, so let no one rend asunder that which God has joined, with Himself.
The mystery of the Trinity is pretty 'out there' for people waiting for things like world war three with a visually mighty deity turning up, but they shouldn't be changing the Bible, regardless. We don't get it so we'll change it isn't it for me.
Bang