Woah I was literally just commenting that I miss that expanded toolbar layout. Unfortunately that option isn't visible yet in my Nightly, but this indicates that it might not be gone forever, awesome!

Edit: Just enabled Secret Settings and now I have back my beloved toolbar! It's a bit chunkier than it used to be, but still neat.

Edit 2: ah, and no back/forward buttons, that's a shame. I'd prefer those over the bookmark button.