Richard Patterson, NEC4 drafter, wrote an article for ICE’s Management, Procurement and Law journal entitled "NEC3 to NEC4 – evolution, not revolution; some fixes and some good ideas!"
In this article he provides his views on the NEC4 suite, including what changed and what's new.
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law.
Volume 170 Issue 6, December 2017, pp. 264-271