Perhaps, but it would be good to know what exactly it is trying to download. It doesn't seem to specify anywhere. I've only had WoW back on my PC for the past 3 weeks or so. What I did was:
Did a clean reinstal, all the way through from vanilla followed by each expansion until Cataclysm. It took forever (and makes me wonder what were they thinking with vanilla WoW and BC on 4 CDs each?!)
Noticed I had to download 13GB of patches, and decided no thanks, not on my 5GB per month cap.
Copied a friend's WoW folder and merely tossed it over my current one, thereby replacing all the game files and updating it to the latest version.
Been playing extensively for the past 3 weeks without any issues.
Saw it wanted to download the 6.1GB patch for 5.0.4, and decided to prevent it completely (I only have a 5GB cap, so giant patch downloads at home won't be working for me)
Drove to a friend yesterday, and copied the TempMig folder. When I got home, I saw that I already had the TempMig folder in my WoW root. Strange that, as I didn't download it, and definitely didn't copy it the first time from my friend's PC (I still have his WoW folder on my portable HDD, and the patch is not part of it).
Started the Launcher. It had no problems updating the Launcher, but the moment the new version of the launcher started up, it wanted to dl around 8GB.
Opened my WoW folder again, and noticed the TempMig folder was missing. I copied it back over, restarted my PC and everything, but it keeps wanting to download 8GB.
My friend managed to download and patch his WoW without any problems whatsoever.
Perhaps I should allow it to download until it only requires around 5.9GB. I will need to buy more capacity though. Last resort is to go copy someone's WoW folder again. Sigh.
i am in the exact same boat, also downloaded the zip file of 6gb.....when the MOP launcher appears it says i must download 13GB
So if i install MOP i still hav to download the 6GB+ patch file
No, you won't. I would assume most of that 6GB is the new Pandaria continent and all of its content. If you're still on some Cataclysm version, installing the Mists of Pandaria expansion from its two DVDs should give you the majority of the required data. I would guess you would only need to download small incremental patches to get it to 5.0.5.