I was away from Kinetis for several months and I've just had a chance to spend some time looking at the code of the Kinetis SDK 1.0.0 release. I am very impressed. This is nearly everything I was asking for — I used to be rather disappointed with the state of library support for Kinetis devices.
The SDK is working together with CMSIS, which is great. It supports bare metal, and most importantly it aims to provide a system-level interface to certain components (a clock library and a power management library were sorely missing, I was about to write my own). Overall the code looks fine, and I think this is a great direction to take. Don't introduce too many abstractions and layers, just provide a good interface to the underlying hardware.
It still fails short in some ways, but I'm hoping this will improve quickly. Notably, the I2C master driver only works in blocking mode (which I why I'd still use my own code for this).
The biggest shortcoming, though, is the list of supported devices. I use KL05, KL25 and K20 in my projects, none of these are supported. What's worse, there seems to be no roadmap, so I don't know whether I should wait for the SDK to improve, put the projects on hold, or write code myself? On a practical level, right now the whole Kinetis SDK effort is a nifty demo from my point of view, with zero practical utility.
Please: it would help tremendously if you could a) try hard to support most Kinetis devices, b) post a roadmap of device support so that we know roughly what to expect.