iOS was redesigned to take advantage of the larger screen. Both the iPhone and the iPad are based on multitouch input, so there is no reason to change the interface for the sake of change.
Some of the apps were; iOS itself was not. With Honeycomb, you really get the feeling that Google put android on a tablet and then thought, "what needs to change to fit this form factor better?" With iOS, you really get the feeling that Apple put iOS on a tablet and thought, "Why don't we let them put 6 icons on the dock instead of 4!" Here's a few examples of what is different than Android on a phone:
1) Home screen: Search button. Honeycomb has a legitimate desktop with customizable content. Optional widgets (that actually look really handy, re: gmail/calender widget). Shortcuts to much more than just apps. Access to notifications and settings.
2) Browser: Honeycomb has actual tabbed browsing and can optionally support flash.
3) Multitasking: Honeycomb uses fast-app switching and shows a vertical list of thumbnails with the current app state.
4) Notifications: Well... you know.
These are just a few examples of functions that Google modified so they work better on a tablet. Apple didn't change anything about the UI to fit a tablet - even down to the same 4x4 grid of icons on the home screen. Where do you think the criticism that the iPad is just a giant iPod Touch stems from?
As far as the thread title goes: no. I don't think Apple will modify the layout of the UI on the iPad with iOS 5.