Whatever new features are to be included in the next iteration of the iPad, one thing you can pretty much count on is that the retail pricing will stay the same.
Apple has their pricing model pretty much perfect. They aren't going to try competing with the $199 Kindle Fire for a very good reason - they'd lose money (like Amazon is) doing so.
Conversely, putting the entry-point price anywhere above $500 will give an opening (no matter how small) for the Samsungs and Acers of the world to try undercutting them. Not going to happen.
This, more than anything else, will determine IF, and or when, you will see a high resolution display on the iPad. If they can get acceptable yield rates at an appropriate OEM cost on "retina" type displays, then you'll see it on a future iPad. If not, you won't. The market for a ~ $700 entry-point iPad is a tiny fraction of that of a $500 one. And what is, from Apple's perspective, far WORSE - is that a $700 entry-point iPad would give competitors room to get into the market.