I don't remember where I was when it happened, but I remember very vividly when I found out about it. I was in a bookstore and read about it on the blurb of a book. I believe it was the paperback of Forward the Foundation (I wasn't very "plugged in" then and didn't get the book until May 1994). As you say, I was struck almost as if a family member or close friend had died. I don't think I ever wrote a poem about him but, for many years, I wished to become a writer because of him so everything I wrote came from him in a sense.
He was an incredibly knowledgeable and industrious man who was endlessly entertaining and informative and, while many fail to appreciate it these days, he was possessed of extraordinary style. It is very hard (and, these days, apparently impossible) to write with perfect clarity and transparency and to use language as a precise instrument for revelation as opposed to obfuscation.
I still miss him - his direct works and his contributions to the field. While not everything he wrote was a masterpiece, he wrote a number of them and it's dismaying to realize (over and over) that there won't be any more.