Based on my initial reading, subject to misinterpretation?
It appears that the feature previously know as NS3 "song mode" is back, and more capable than ever

. The top level construct is a Program which invokes a set of Section Presets. Programs can be organized via the ORGANIZE button (as before). You can run sequentially, by category, by bank/page, etc.
512 programs, which is organized in 8 banks with 8 pages each, with each page having 8 programs. For my use case (setlists), I can simply step through sequentially as before, or (hopefully) use user categories, etc. Plenty of functionality there.
What I didn't appreciate is the re-usability of the program components via Section Presets. I've dialed in my sounds on my Nord so often as I build new voices it's sort of second nature by now; this changes that. Come up with the perfect EP, organ, synth, etc. and save it as a Section Preset. For synth work, you can sync parameters (e.g. mod wheel filtering) across the edits with a special button press. Plenty of section presets (2x64 for piano and organ sections, 8x64 for synth section), and very nice that a section preset also saves your FX as well
This is all starting to look very nice indeed. It will take a while to figure out how best to use it all, but now there is a lot more there than before, and certainly worthy of the NS4 designation.
I think I have gear issues ....