I always appreciate this mic discussions. I suspect the first obvious miking that I heard -- Pearl Bailey's Dolly, National Theater tryout, Washington DC (high school; fall of '67) -- might've been something like the Streisand sound. It was obvious that no one else had a mic but Bailey, and it had a decided "captured" quality, a sense of the performance standing apart. My mom and I even talked about it on the drive home. The Bailey vocals were charming -- she could certainly sing beautifully -- but hers was not a big voice, and the mic made sense. Yet it was odd that her dialog stood out, too. If memory serves. I was of course startled to learn that Promises, Promises (which I saw in the same DC theater in the fall of '68), famously one of the first shows to carefully structure and isolate instruments in the pit and allow the sound mix from the back of the house, per the composer's wishes, did not use body mics (I have a friend who stood by for Fran). People have argued this for years, but as the expert Alan notes, it's never been an exact science until recent decades.
I'm now wondering how obviously the Streisand vocals stood apart.