what do you think is the holdup with the update? The chips are out and clearly they cannot be waiting for OSX as that would make no sense.
So what else could be the issue do you think, please?
I think someone mentioned that the intel HD 5100 and 5200 GPUs haven't been released yet so apple is waiting, either that or like that Kuo guy said that they will be delayed due to the retina display. The latter is probably unlikely since they are able to ship them now I don't know why a new CPU/GPU would hinder the development of the displays for the new computer unless they're doing some design changes. Either way the fact is it's delayed and me and many others are pissed and I just am hoping to god it's released by August.
Why are you assuming there is a hold up, it could very well be that apple was not planning on releasing the Haswell based MBPs yet.
Since apple is so secretive any talk about what it may or may not be is pure speculation.