So ever since last night, I am not even sure what happened, but it was after the update, I was able to play just fine. When I go to open diablo 3 now from the battle.net launcher, I see the Diablo 3 loading icon come up, but then it goes away, and in the launcher it says "Playing now" and the button is greyed out, but the game never opens and the only way to close it down is in the ctrl+alt+delete screen under running programs.
I'm not sure where this should be posted so I figured I would post it here. Also I am having one other issue thats been ongoing for a while. When I open the battle.net launcher and it goes to the "Updating battle.net", I get an error. But when I just go into the folder and click on the battle.net icon, and avoid launcher, it opens just fine.
I had to reinstall the Battle Net desktop app to get the game to load the day after that mini-patch...
I don't know if that will help you but maybe try it (fairly quick and painless) before you go down the long and winding tech support road. Good luck.