I really dislike the way people use the phrase "redesign". The 16" is a redesign. In many more ways than you'll ever realize or appreciate. Unless it visibly looks dramatically different, you'll just call it "the old design".
The 16" redesigns the display, to fit a larger display into the same size housing as before. Undoubtedly the display itself features new display technology yet to appear in a Mac laptop.
The 16" redesigns the keyboard entirely.
The 16" will have a whole new class of internals: CPU, Storage, RAM, Graphics.
These all new design attributes will premiere in this product, and trickle down to the rest of the MacBook line over time. There is no other kind of "redesign" on the horizon.