you'll never see a light version of osx on it.
the rumour is that they are working on a hybrid iOS/os x for future ipads, but even that rumour has it as a more advanced version of iOS, not a slim osx
as for a usb port, sadly i can't see that happening either... the apple port will continue to be used with the adapters being sold via apple (sd card, HMDI)
all in all the ipad 2 was a let down, with insiders saying that the retina screen and other improvements are to be held back for ipad 3.
and as for flash, no chance... apple will simply not go back on this now, too much has been said and written about it by both sides for apple to support it.
although you can get a third party program that supports it via cydia