If you look closely at Carl Zeiss's line of "C" lenses, you'll notice that these are modern versions of its classic Contax lineup:
- f/1.5 50mm Sonnar
- f/2.8 35mm Biogon
- f/4.5 21mm Biogon
All of the originals were compact lenses, and so Zeiss is able to cater to two groups: Those looking for compact lenses, as well as those looking for modern-day equivalents of classic Contax glass. And in this case, they get true Zeiss lenses, and not someone else's interpretation of them.
I don't think we'll see a revival of any prewar designs, including the Olympia Sonnar, the f/8.0 28mm Tessar or the 160mm Tele-Tessar.
A re-release of the 85mm Triotar could bring a very good and lower-cost alternative to the f/2.0 85mm Sonnar to the stable. The 85mm Sonnar itself is a recreation of the Contax classic portrait lens.
I would really like to see a 135mm Sonnar, which this camera's rangefinder could easily handle, although rather than the f/4.0 original, perhaps an f/2.8.