Biggest issues for me are the missing left hand quick access...

Biggest issues for me are the missing left hand quick access menu and the fact when you compare old to new side by side, the new site, despite what is said, has a lot more whitespace and clutter and the post section starts lower down as a result, and of course the post lines are more widely spaced.  Never mind the fact it is harder to decode at a glance.
As I intimated..... new widely spaced layout is appropriate if you are a macdonalds eating, fat-greasy-fingered smartphone swiper, but a tangible step back for those using that most efficient productivity tool ever invented.... the mouse.