After all, this patch is just a question of tweaking some numbers, no new content, so why is it so big ?
Likely because of the optimization and Esamir updates. Also if I recall the notes there will be a new pistol.
You have to keep in mind just how big in size these textures can be. They're retexturing an entire continent, so they basically are rewriting the entire continents files on your machine, that in an of itself is a huge chunk of space, not counting all the other things they're rewriting.
