What about symlinking files onto a software ram drive? Its no problem to assign a portion of your ram to make a super fast (yet small) "hard drive". Imagine if you could symlink the data folder that contains maps & terrain onto this super fast drive. Lets say the maps for Dalaran and Battlegrounds, you should arrive instantly at this location with no loading (apart from on-the-fly loading of characters, armor etc).

The data-folders from Doom 3 are compressed into .pak archives (or something similar), these can be extracted to decrease loading times (since the game doesnt have to extract during every loading sequence).

If it is possible to extract the .mpq folders in WoW then it should also be possible to symlink files of your choosing onto a super fast software ram-drive. Preloading the files so they dont have to be loaded during play. It would not cost anything as you would just be using the spare ram you have anyway.

This is something Im gonna look into, I think it will work and if it does then I will always be the first to enter any Battleground - all of my toons would occupy group 1