One of the priorities in Plasma (desktop and active) is to have a compelling developer story, to make easy, fun and desiderable for people to write plasmoids and actve apps.
As I described in the latest entry, with the KDE Plasma Workspace 4.6 there will be a new feature that will be a key one for the future evolution of the Plasma platform: the ability to write plasmoids with just QML and Javascript.