JOO-lee-et.
Juliette I'd pronounce with the emphasis on the last syllable. I only hear people pronounce
Juliet with the emphasis on the first syllable. I had a neighbor once who pronounced her name that way too, but spelled it
Juliette. I personally would just emphasize the last syllable in that spelling because I think it sounds pretty. :)
I don't think it's getting common or that it's tragic. I've only ever met or heard of one Juliet(te) in real life before, she was probably born in the early 80s.