My list contains things we won't have. Like being able to use FaceTime with someone who has a Motorola Xoom. Or being able to print to any printer, not just the ones Apple says we can. Or maybe even having an extremely thin keyboard that slides out from the bottom ... see, listing my wishes is pointless :-).
I think we'll continue to see better cameras and faster CPUs. I think the browser will improve even more. I think we'll continue to see cool new native apps, like Reminder and Messages. But I don't think we'll see any physical hardware changes.
I'd like it to be lighter. And if that means slightly smaller, that is ok for me too. Something that is easier to hold in one hand. A flash would be nice. And Siri! Slightly better speakers. I had to use an Asus Android tablet for some testing for a few days and the speakers on that thing were better than the iPad. Unfortunately, it ran Android.
My list is mostly tech: faster, better display, better WiFi, better 4G cell data.
My biggest item came with IOS 5, wireless sync.
I don't see the need for any camera on the iPad, but I know most folks think its cool. Similarlly I don't think Siri is vital, I don't see talking to my computer. I can see Siri on the cell phone, but my iPad lives at the edge of my favorite chair, and I can easily touch it.
Of course, as a developer, I am not a fan of a better display, as I'll have to do two layouts, one for the old display and another for the new, twice the work, twice the graphics, twice the QA effort.
In the never gonna happen but I'd wish anyway, I'd say lower the price. Lower price means more units sold which means more folks to buy my app.