Since getting my iPad Air 2 last week (I upgraded from an iPad mini), I noticed two things about the display: if I get closer to it, I can (almost) discern pixels again; and, it's considerably better than the iPad mini when used under indoor lighting.
A major innovation for the iPad Air 2 (that is not fully appreciated) is an anti-reflection coating on the cover glass that reduces ambient light reflections by about 3:1 over most other Tablets and Smartphones (including the previous iPads), and about 2:1 over all of the very best competing Tablets and Smartphones (including the new iPhone 6). We measured a 62 percent decrease in reflected light glare compared to the previous iPads (Apple claims 56 percent) and agree with Apple’s claim that the iPad Air 2 is “the least reflective display of any Tablet in the world” – both are in fact understatements.
While the anti-reflection coating doesn't do much in direct sunlight, in my experience it has an effect for working with the iPad indoors. As for the pixels, it's not a big deal because I wouldn't normally get my eyes close to display (so in normal usage, the Retina display still looks fantastic), but I'd definitely welcome a Retina HD iPad next year.