Welcome to the forum, and to C-Max ownership. I'm another 2012-vintage build, now at 43K miles, and planning many more. I'm also concerned about the tranny.
Someone recently posted a link to the Advanced Vehicle Test Activity, which includes hybrids. They buy and test cars, with periodic measurement of battery capability and a full list of service actions. Don't look at the Malibu, it's a disaster.
It is worth noting that you can't compare the 2013 Malibu with the new Malibu hybrid that is being released. The 2013 was more of a mild hybrid, with a very small electric motor connected via a drive belt. The new Malibu hybrid will be using the same technology that is in the new Volt, just without the large battery and ability to plug in. I'll be interested to see how it holds up and what fuel economy they get in real life.
I looked a some of the tests. Great stuff. Very interesting. It pains me to see 1 out of the 4 Cmax lost a tranny so soon. Im planning on keeping this car quite a while and handing it over to my daughter in several years when she recieves her drivers license. We put less than 10k miles a year on, so she would have a vehicle with less than 100k in good condition as i plan to maintain it properly. I remember my first vehicle was a 1982 toyota pickup with a road sign in the floorboard to cover the big rust hole. So hers will be quite an improvement over that. Anyways, i woukd think a vehicle like the Cmax should go 200k or more before a tranny went south. That may be asking a bit much for some but i personally dont think so. My 2006 prius at over 150k showed no problems whatsoever. I trusted that car to drive anywhere. I hope im just over worrying. Also, is it safe to say the cost of a cvt replacement will drop as years go by?
The big expense is Ford claiming the entire powertrain must be replaced, you can't replace the CVT alone. Perhaps someone here is more knowledgeable, but it sounds like the electric motors are integrated into the powertrain, meaning it is very labor intensive to fix only the parts that failed -- not to mention, a part in the CVT failing likely has a good chance of damaging other parts of the powertrain.
The other point is that it seems there is a flaw in only some of the original CVTs, such as Ford possibly getting a bad batch of bearings that weren't caught before they were installed. So, if your car has one of the defective parts in the CVT, the car likely is a "ticking timebomb" until that part fails (such as the 1 car of the 4 that went to Advanced Vehicle Testing). But, that testing would also seem to show that if you didn't get the bad part, your C-Max should run reliably over 100,000 miles (one C-Max currently has 131,000 miles with no major issues) -- though we'll see how the remainder of the testing goes (they are scheduled to be driving to 195,000 miles). It is worth noting that all the cars used in the Advanced Vehicle Testing seem to run a similar City/Highway mix, basically all being used by the government as messenger cars in the Southwest US.