the html5 app won't be capable of using device specific input, such as accelerometer, compass, multitouch, etc. All of that is not yet part of the html 5 spec.
So when we compare html5 vs mobile apps it's just an apples against bananas type of comparison
Well, the strategy i'm describing involves a native app. In that case, would it be possible to expose device-specific API to JavaScript?
Also, multi-touch is actually supported by webkit. There a nice WWDC video that intoduces this capability if you'd like to learn more.
To be clear the idea above isn't new of course. For instance http://www.appcelerator.com/ provides a native app with a thin wrapper around a web control.
Phonegap provides a thin wrapper around a webview.
Titanium changed course with their 1.0 version, and now compiles the Javascript to native code. (they used to do the webview thing).
