Nokia’s unfathomable commitment to Symbian is no secret. Nokia has released some concept proposal UI for Symbian^4 and is currently asking for feedback from Symbian developers. The Qt built S^4 UI boasts revamped layout, support for irregular shaped homescreen widgets, improved task-switcher and more.
Nokia has in fact, compared the UI to Android, webOS and iPhone OS and claims to improvise them at various fronts.
The S^4 UI is expected to arrive later this year after the S^3 update.
Concept Proposal [Doc]
[Via Slashgear]