On the hardware side I don't think there is much that needs to be done. More power isn't needed by any application and shrinking the bezels will inpact the usability. The device is a million different things to a million different people and messing with stuff impacts everyone.
But the hot mess that is iPadOS? That needs some clearing up. Its high time Apple moved it further away from its iOS father and transformed it into something that better suits its larger form factor.
There are two areas they need to clean up: wasted screen space and illogical interactions. The widget dashboard and the Stage Manager both have the same gesture to summon them. With an app open the 'stage' slide-in and the multi-tasking slide-up both have the same exact function. Notifications take up too much of the screen and control center takes up too little!
Just because it has a keyboard doesn't mean that the iPad needs to be just like the Mac. Accessing widgets within apps is useful so keep the dashboard but let us have a whole screen of widgets instead of one column. Get rid of the slide-in stage interface (which only shows a limited selection of open apps) and double-down on the multi-tasking screen. Move notifications to the Dashboard display, sat in their own column on the RH-side of the screen. Put more system information into the control center.