Really what this boils down to is that the old Summary page provided an operational snapshot of the business, which the new Summary page provides more of a financial snapshot.
For me, I hugely preferred having the operational view. When I needed a financial view, I could run the appropriate report. But what I want to have in my face whenever I open Manager is stuff like how much money customers owe me and how late they are with their payments, how much time I’ve accrued and not yet billed, and how much cash I have on hand – and the old hierarchy, with its actionable links, was very helpful to that end.