I very much doubt it will pack an octacore chipset. Not with the release date standing so close. Not that it really matters that much, lets face it. It is not like the S3 is sluggish....
Am I the only one who as yet to see any tangible improvement over the S3 in these rumours?
Slightly bigger screen with FHD. I very much doubt we'll be able to notice any real world difference between 720p and 1080p on a cell phone. Less colour shift at wide viewing angles, improved colour accuracy and the possibility to calibrate the screen are more important towards better screens than ppi count.
13MP camera? I wish manufacturers had stopped this pointless pixel race already and took steps to really improve image quality - bigger sensors for starters, improved quality in low light, better quality optics, etc. Oh, and is it so hard to put a physical shutter button on the phone? It is not like space is lacking...
Alas, I fear the S4 will just be an S3 with minor "improvements" in order to keep the yearly update cycle of top-of-the-range phones.