Yeah, I'll say others are innovating when they beat apple at design and engineering (ie. thinness and lightness). I doubt they will soon though. I don't think 1080p smartphone screens are very innovative, unless they can be proven to be substantially better than the ones we have now. It seems that the DNA sacrifices brightness and color saturation for a hardly discernible gain in sharpness. And the performance/battery hits don't seem very worth it.
I'd be all for 440 PPI, but I don't want any compromises. That's why I didn't buy the iPad 3, the tech just didn't seem ready yet.
I just wanna say that the term "innovation" is tossed around way too much. It's such a subjective thing, and difficult to argue. Is Android 4.2 innovative? They added PhotoSphere (basically just Photosynth), lockscreen widgets (OEMs have had this), Quick Settings (ROM community and OEMs have had this), Gesture Typing (Swype), and that's about it. Is the Nexus 4 innovative? No...unless you believe taking less profit is innovative.