Some people have already figured out the sidebar is gone. It's been gone on mobile devices for ages but not it's gone. RIP.
The sidebar used to be a source of ad revenue but has been declining since most people don't click on mobile ads. C'est la vie.
Other than that, I love the new typographic and see a great business for people who can make/sell theme mods. I mean if 3 million people set up their blog with one of the three basis theme header images - yecch! I want to be unique not the same...so something different, something creative has to be done here.