Glad I'm not alone, hope apple is aware.im going to send them a email about this as well.
I doubt its an error. I'd estimate photos were compressed to about retina resolution on the iPad 2 to shrink their size but maintain the ability to zoom in reasonably.
For the iPad 3, obviously that would merely be the native resolution and they'd have to allow for at least double the res for zooming in and showing off iPhoto, which is probably just leaving them at their full size.
If you want them to be smaller, create a separate folder for photos you want on your iPad and compress the files yourself. Or don't synch every photo you have...
Why don't you guys just check the size of your photo folder on your pc/mac. I bet its the same as whats on the iPad. Minus the extra images you may have from the iPad itself (photos, screenshots, iamges apps save out) or an iPhone photostream and such.