Samsung is releasing SDKs that mean developers can target their devices for capabilities beyond stock Android. This comes at a time when Google is tightening it's hold on this "open" platform and the only devices in the ecosystem that matter are from Samsung.
I find this immensely gratifying since I once had a reputation as "the fork guy" for advising clients this was a likely future, though many years ago it wasn't at all clear Samsung would end up in such a dominant position. (I one thought Motorola most likely.)
Now that it's clearly unfolding, all the doom-for-Google reporting is overlooking the Android fragmentation problem that KitKat seeks to address (and Apple has become bold in pointing out). It's really a Samsung fragmentation problem, as their own product line spans a dizzying away of screen dimensions, hardware capabilities, and OS compatibility.
Samsung has succeeded, wildly, with a carpet-the-market strategy with a portfolio of countless products. This causes the fragmentation that frustrates developers and creates confusion in the app market, and Samsung will have this heterogeneity whether using a Google-controlled Android, self-controlled Android, or even TIzen.
We're still some time from the Galaxy SDKs being consistent enough to be broadly interesting to developers, or scary to Google.