Yeh this is something that Sencha could certainly take a look at, especially with the regression of the localstorage persistance in the newest ios.

PhoneGap works fine also, there really shouldn't be performance differences between the two, just phonegap will be a bit awkward to setup at first until we have a working template.

I know there are tutorials and other threads around that guide through a phone gap package - let us know how you get on. I may be able to help somewhat - I have packaged many an app in phonegap, just not a sencha one as of yet...