Well see, let's unpack that for a minute and look at their claims. I have control of the arp of each layer on N3, it was one of the big selling points. There do seem to be some useful tweaks in the arp - it's very clumsy in use in N3 - but I don't get their headline claim that control over each layer is anything new.
The Librarian. The first two bullet points - "Featuring three columns for easy navigation. Counters for folders, categories, and presets to give you an overview at a glance". Lovely! And exactly what I have in N3.
Similarly, the first bullet point in the effects is "Full visualization of the signal-flow for real-time feedback". Like... in N3! The signal flow is clearly there. Again, there's a few new useful things - two new effects I think - but overall their blurb seems to me telling me that I really must have this great new feature that I already have.
This goes to the heart of why - as I type - 84% are not persuaded to upgrade. The feature list is so light, they have to lead with features we already have. Most can see through this pretty quickly. I think for new customers N4 represents a solid buy, just as N3 did with an extra 1% of fairy dust on top. For upgraders - nah.