Most of you seem to suggest that the bigger iPad needs to be bigger and faster...
For me, I think that the only way the big iPad will survive the cannibal is by becoming lighter and more portable.
If the full sized iPad becomes portable, it would be much more difficult for a miniature iPad to take over. Think about it, if carrying around a full sized iPad is as easy as the iPad mini, except you get more screen real estate, will people still choose the smaller iPad mini over the full sized iPad? Only if price were a concern (and that's why the mini was introduced right?). If they slim down the next iPad closer to iPad 2 with retina display, I'd be very tempted to upgrade.
I also think trimming down the bezels to make it look more modern wouldn't hurt as well, but that's not up to me,,