a few years back Facebook had natural language search; you could search "show me all photos of me and Sarah" and it worked well

given all the hullabaloo about nls today, any thoughts on why the deprecated it?

It was a great feature! I was recently putting the same search queries and didn't get any response.

no one was really using it and it was hard to maintain

Parts of graph search are still there, but it used to be so much more powerful. I would guess that Cambridge Analytica scandal and privacy blowback are part of why it was neutered.