Scaling up also means "the middle third of North America is going to explode tomorrow", so this is an on-the-run sort of plot. Backstory occurs in brief intervals between Harry getting beat up, performing his own beat-downs, and meeting up with allies and enemies for collaborative beatings.
Molly report: roughly the same as the previous book; she is no longer an apprentice and Dresden is coping with that fact but still absorbing it. (Mab delivers an extremely cynical lecture on the subject, late in this book.) In fact Dresden doesn't have time to absorb much of anything in this book, except for disaster reports and the aforementioned beatings, but the author is clearly willing to switch up pace and tone between volumes so the next one should provide some resolution in this sphere. Especially given certain Molly-related story developments which even Dresden cannot manage to ignore.
I do not have a clear sense of how much farther the series has to run. Many plot elements are clearly escalating (even after Lake Michigan is defused). The author could aim for a massive arc climax in, say, two more books -- and either wrap it up there or just crank them out forever, I have no idea which.