Z-buffering is yet another one of Jagex's failed attempts at "improving" the graphics, let alone completely forgetting the fact that you can't really do a lot on a 10 year old Java Engine without everything being glitched to fuck after the rendering process. According to Jagex, its to fix "cliping issues" which was about 7 MINOR errors which no one cared about, yet they MUST crash the servers for 4 hours in order to binary-rape the entire game engine.
So what's new?Edit
Nothing,apart from the wilderness ditch being replaced by a wall that looks like year old poop,skillcapes nerfed by having their inner trims removed and the female one shortened(This has been fixed right away!) and false promises about how "graphics will be improved,better combat animations and some other bullshit.However one good thing was that High detail became faster(no link to bullshit :O)than Standard detail.