BTW, last year Nikon filed patents for an 18, 20 and 135mm 1.8 g's!
Yes, you can see Nikon slowly replacing the older design lens,
Of my older AF primes, the one I like the least is the 20mm, but I bet the new one will be very expensive, my guess is 1400 dollars! I still have trouble paying that much for a simple prime except for beautiful examples like the old 105 DC,, what a beaut.
If the 20 mm G redesigns the flaws of the current 20 mm AF D,, and priced at say 750 dollars,,, then,, could be a great choice.
When I want to carry a 20mm, I actually use my 20mm 3.5 AI lens,, way nicer then the 20 mm 2.8 AF D. sharp, no vignetting. and super super compact. seriously, if you have a FX camera,, picking up one of these classics is valuable addition to any kit.