I don't get the fuss about it....yes he was a brilliant developer, back in the days when 1 person would make a game like Civilization, Populous, Elite and so on.
Then things change, 1 person won't make the difference anymore, since the team are made by hundreds of people, the engine are purchased and sub licensed by other companies (not his case, since he was the mind behind the various quake engines); and overall the focus is to make the next AAA title to release in time for the holidays.
He is an antics of a past era; and it is right that he take off and go experimenting new things...nobody nowadays uses assembly anymore, so his super skills are quite useful in certain fields only nowadays, and that's why at the Oculus he will probably make something amazing.
But game wise, I don't see the point in even mentioning that he left ID (or they let him go; whatever it is), after all he was already done since long time ago...other than Doom franchise (and Rage), is not like he did many other things. They beat that Doom horse until it was not dead but already dried up 🙂
Good luck JK 🙂