The M42 mount seems like a stop-gap maneuver of limited appeal. Only dyed in the wool Zeiss lovers will go to such lengths as to use uncoupled, stop down metering lenses ... when the remainder of the world has moved on to AF, or at least fully coupled aperture control (shooting Makro is an exception of course, because it is a more deliberate method of shooting).
I've been using Zeiss lenses like the 85/1.2, 28/2, 35-135/3.3 and 70-210/3.5 on Canon full frame DSLRs. But in truth they are difficult to use in real practice ... unless you use them wide open most of the time (which is primarily how I do use them). None of the new FZ lenses hold any appeal for me. They are redundant focal lengths if applied to my Canons, I certainly am not dumping more cash into the dying Contax C/Y system sitting on my shelf, and more certainly, I'm not switching to Nikon because (IMO) they are headed for the grave if they don't get a full frame digital sensor with-in a year or two.
However, I think Zeiss may have something up their sleeve with-in a year or so. Something that will rock our boat. A hint about what could be coming can be detected in what they did for Sinar : -)
I'm done spending hard earned money on the ever-changing, fickle world of modern photography. With film cameras dropping like flies, film companies disappearing, and volatile pricing of everything out there ... I will apply what I've learned from the swirling world of DSLRs ... I'm going to wait.
In the meantime, I shall use what I have and stop fretting about marginal improvements designed to suck more money out of my wallet to save some lens company or camera maker.
I will act only when the innovation is a quantum leap forward. A Zeiss series of AF lenses with fast apertures and blazing focus speed ... and fully coupled controls would do that.
Zeiss heritage is one of supplying superlative quality lenses that professionals aspire to and advanced amateurs covet. For 35mm in today's world that means AF. If I want superb MF 35mm lenses, Leica makes everything I need or want... including a Camera I can put them on. I don't think there is room for 2 manual focus lens makers in a world of shrinking demand.
I am determined to vote with my wallet, and send a message to all these lens and camera makers ... no compromises. Lead, follow, or get out of the way. Zeiss is a leader, but they are acting like a follower. Time to take the lead again Mr. Zeiss.