Razor-thin device with a thin bezel. Because most tablets are way too thick.
No buttons PLEASE! Only a power button, and if possible, make it click behind a piece of plastic, effectively making it completely water-proof! Meaning none of that speaker sieve crap. If you do add speakers make sure no one can spot them at a glance and that they'd have to place their ear right next to it to be able to find out where they are.
10h+ battery life.
USB 3.0, HDMI.
3 models in: 8, 32, 128 GB capacity - the high-end model sporting a Wacom layer and an embedded stylus.
Android and Windows 8 in a dual-boot configuration.
Make it happen, Dell !