Thank you for your response, really appreciate it.

In my perspective what you describe is not really an issue but a way to improve a specific behavior. It’s totally fine to not have weak in GCD or Alamofire, but you have to keep in mind that the piece of code will be called even if you have left the ViewController. Sometimes, it indeed makes more sense to have weak, to prevent the code from being executed, when the ViewController is not used anymore.
The call will not fail, because the closure has kept a reference to everything it needs, but it might not make sense.