I have been following on TouchWIZ and its evolution since it started and now after almost 18 months since that happened, Samsing is now opening TouchWIZ for third party developers via a SDK. The SDK could be seen similar to the palm pre WebOS that is limited to web tech like HTML, JS, CSS and the like but at the same times that makes it quite easy for everyone that wants to get into to just do so if they are already familiar with web development.
The hook is that TouchWIZ is not only a Widget UI-UX that is used in Samsung own in-house OS but also works in Symbian and in Windows Mobile. Given the uniformity of how its works in such different Mobile OSes is quite sure that if Samsung want to use it in Android and Maemo. TouchWIZ will work in these mobiles OSes Too. So that is quite a hook to lure in widget developers. Being able to have widgets running in almost all of the top Mobile OSes with ease.
TouchWIZ widget engine should be considered as the best and more pervasive widget engine in mobiles right simple because its influence on LG and most of Korean manufacturers in this space copying from it. It has now been is many phones and the first big mover advantage (with this kind of design) they had made many to think about competitors offerings in TouchWIZ or even calling it that without knowing it is not actually TouchWIZ.
So having a SDK will be very interesting as it is very likely that LG and others will follow suit.
Go to the Samsung site for the full details.