I see many browsers being developed for mobile. All of them still use HTML,CSS,JS for rendering web page. Why not replace it with a different presentation format that is suitable and efficient for mobile ?
No, like browser 2.0 with different presentation format.
Mmmm I do not see the point, you can do (almost) everything with web apps that you do with native apps. A browser that introduces a third set of tools will just make things worse. Maybe your idea should be to build a browser that exposes all device functionality to web apps.