One of the features added in the recent patch was a new death animation that looks pretty amazing! Check out what Typhun of Warcraft Legacy has to say about it, including some screenshots of the effects themselves:

I thought this was so cool, that it was news worthy. The new death animation. Previously, everything looked the same in death as it did in life, except you couldn't see enemies or anything, except around your corpse. Nothing was different except that. Now, there is this awesome effect. You can't really tell from those screenshots, but it is really foggy too. It was a shock when I logged in on a dead character, to that. When you ressurect, it has a cool effect as well. There is just a sudden return of color to the world. Very cool effects by the Blizzard team.