Here’s an excellent article: What Happened to “O”, by Gabe Rivin, posted by The Paris Review, which traces the arc of O‘s popularity and eventual decline in the English language, and discusses changes in language usage, in general. On the loss of O, Rivin notes:
“I felt a sense of tragedy as I considered this loss. Yes, languages change, as do cultures. But O hadn’t just been replaced by oh. The transliteration wasn’t perfect. O seemed to have a unique emotional resonance. Its speakers, I thought, were desperate and alone, enfeebled somehow, and yet joyously willing to confront powers beyond their control.
Now we’re almost entirely left with oh. As in, ‘Oh, I didn’t know the printer paper was out.’ We seem to have lost something, an underlying sentiment that was unique to O.”
I love O. A well-placed O can be delightful and surprising, as well as poignant–often just right. However, other than coming across the random satirical usage in modern writing, I guess I’ll need to get my fix from older texts. But O, how I do mourn your disappearance!