Is the 15" Retina going to get that much of a bump? Haswell I really don't care about that much but I'm more concerned about the GPU. Is it just worth it to wait?
Well at this point you're only looking at a 2 day wait, so it would be kinda silly not to.
Even if the Haswell update doesn't seem worth it to you, you could then get a better price on a 2012 or early 2013 model from a reseller or Apple's certified refurbished section.