This is mostly an argument against making AppDelegate into a God object, which I totally agree with. It's not saying singletons themselves are inherently bad. I

This is mostly an argument against making AppDelegate into a God object, which I totally agree with. It's not saying singletons themselves are inherently bad. It does generalize saying that they usually make it difficult to evolve an app's internals, but I disagree with that. As long as they're chosen when appropriate, and used properly, there's no problem.