Retina is no use unless they start putting in decent graphics cards, which they wont do because they couldn't cool a decent 4K capable part in the iMac.
Id rather have 1080p and a graphics card that can decimate everything thrown at it at that resolution, than a retina 4k+ screen that i have to either watch a slide show on because the video card cant drive it, or drop the resoltuion so it goes blurry because again the video card cant drive it.
Apples "Innovations" are not always good, they might drop Retina Displays, and faster CPUs, but without the graphics ooomph to drive those screens its like putting monster truck tyres on a peddle bike.