The Defender is 5.5" in off road height (if I remember right) without Johnson Rods. It looks like quite an extensive upgrade to the air suspension. Ever since the BMW L322, Ford and TATA have been removing wheel articulation in exchange for highway performance and stiffness. Which is why a lot of the modern rovers always wave a wheel in the air off road.
It's looking like the new defender is going back to off-road performance with 10.5" or so of wheel travel. The old Mark III ranger rover was about exactly that, and it worked amazingly well.
The only fear is reliability...