I don't see Retina or a size change happening this year, that'll be for the big redesign in 2013. By the way: the MBP uses a mobile processor, the iMac uses a desktop class one and 32 GB is the current max RAM for iMacs.
I see: new anti-glare screen similar to the rMBP, Ivy Bridge CPUs, better GPUs, USB 3, and cheaper SSD and RAM prices for build to order models.
All this talk about a complet redesign in 2013! I have followed Mac Rumors and this forum for a long time now and have read all of the news concerning the iMac. I haven't seen anything close to a relayble rumor that say's iMacs will have a complet redesign 2013, other then Cook's mail clearfication about the Mac Pro redesign 2013 or when ever that will happen. What I am trying to say is that it can be a complet redesign alrady this fall or spring 2013, summer/fall 2013 or spring 2014 we don't know until it's released.
I am also eger to see the new iMac's and as everyone els here hoping it will be soon. I don't see retina if the release will be this fall but maybe later, but it can still be a big redesign.