I am having the exact same problem! My only change is I haven't downloaded any new updates... I was able to play yesterday, and I haven't downloaded any custom content between yesterday and today. I have tried uninstalling and reinstalling the app, restarting my Mac, and resetting the origin app. Help?!!??
UPDATED: Found a solution!!! If you are having a similar problem try restarting your mac into SAFE MODE. (to do that just click "restart" on your apple menu and hold shift until the login window appears.) If the game launches properly in safe mode, then restart your mac normally to exit safe mode. This should solve it, if it doesn't, then I'm very sorry. Try other options that others have found!!!
On your Mac, if you go to System Preferences and open Security and Privacy. Go to General and at the bottom it says allow apps downloaded from: it will give you an option for allowing origin to continue. Happy Simming