Excellent, Apple is responding to the Nexus 7. Don't you just love competition! Apple could do a $50 markup for being Apple, I hope they don't keep their mini pricing at current levels.
How is this a response to the Nexus 7? You don't just decide to put a retina display in the mini on the fly because of what a competitor does. I'm sure a lot of work has gone in to designing a product that still gets great battery life but isn't lot thicker and heavier. And considering how well this product would sell Apple has to know they can meet demand with no production issues. Tim Cook doesn't want another iMac situation. That would be a disaster.