The iPad 3 will not get panorama because the display is way to big. 9.7'' panorama camera. Panorama will be available today for the iPhone 4S and made available in two days to the iPhone 5 and in one month to the iPod Touch.
Has Apple stated the reason? The iPad can display panoramic photos taken with iPhones, so it's hardly obvious why it could not generate them when equipped with an equivalent camera, CPU and OS.
could it be camera quality? I am too lazy to go check but is the iphone5 camera any better than the new ipad camera? Not just in resolution but in quality, speed, etc.
There could be an optical reason. For my DSLR I actually have a panorama head which allows easy adjustments to rotate the camera/lens around the nodal point.
Now on the iPhone the camera/lense is closer to the rotation axis; while on the iPad the camea/lens is more away from that line which could result in less quality images. Just a guess.
I think the camera has to be able to take photos fast enough that you can pan at a reasonable speed. If it takes a second or two per photo you couldn't get a smooth panorama without a tripod.
Also, Autostitch Panorama. It's an iPhone app but it works fine on the iPad. Apple hasn't implemented the panorama feature for their iPad camera app for no obvious reason, since it's clear it can be done.