If the tablet is going to be a first class web browsing experience, as much as it pains me to say it, I can't see how its going to find its way in the marketplace without Flash.
Flash on a phone doesn't make great sense, but on a larger screen like a tablet, I can't see any justification for leaving it out. Mostly, I just want to watch NHL Gamecenter on a tablet
I also think the tablet could open the door wide open for a number of important holes in Apple's strategy:
- wireless sync. Plugging in your tablet to sync with a cable would be teh silly
- home/cloud server for your media. You'll now have a Macbook, an iPhone, and your tablet, and maybe even an AppleTV (or two

). There needs to be a way to consolidate and distribute the media to all these devices that is more functional than iTunes Home Sharing.
- iPhone apps and data syncing on your desktop. I want my iPhone/tablet apps to keep their data in sync - I should be able to check/enter my gas mileage on either device. I should also be able to view the exact same app as a widget in my dashboard on my Macbook. Apple has an iPhone emulator, there is zero excuse for not giving me these apps on my Macbook. If the tablet doesn't run iPhone apps natively, I will consider it a major blunder on Apple's part.
- Tablet should have Back To My Mac capabilities. The iPhone should too, but I'll let it slide because I could see how Apple figures it isn't elegant.