Did you try this and see if it helps?
1. Force quit any Diablo III, Agent and Blizzard Launcher processes in [url="http://us.battle.net/support/en/article/closing-background-applications-mac"]Activity Monitor[/url].
2. Navigate to /Applications/Diablo III.
3. Delete the D3Debug.txt file.
4. [url="http://us.battle.net/support/en/article/repair-file-permissions-and-reset-folder-permissions-mac"]Reset the Diablo III game folder permissions[/url].
5. Launch Diablo III.
- If the game prompts to enter in your administrator username/password, hit Cancel.
- If it doesn't it should load fine.6. Diablo III should load.
Did all this. Still having that "initializing" problem.