I think their goal is the right; to reduce the vertical space usage at the top of the page before the "content". They did however remove some of the useful tabs and keep the least useful. Programming language stats and project description & project URL seems less important to me than the "code, issues, pull request etc" tabs.
Agreed. I've often presumed that stats (esp. language and commit counts, etc.) were part of the "social" aspect of GitHub, but not otherwise useful to me in any meaningful way most of the time.
I think the sidebars are a step back for me. I preferred some useful content at the top, now having it on a sidebar just moves that content to the right side, away from my focus.
One positive thing about the change is that "network" and "graphs" are now not co-mingled with main workflow items like Issues and Pull Requests.
