Nope. I never want my front task just interrupted like that. Let's take your "check the filename or something" example, and while you're there, you realize you also need a new directory, so while you're typing the name, the other task steals focus and the character you're typing cancels the task - and now you have to start it again. This exact situation has happened so many times, and it's why focus stealing focus of any kind is a problem.
I don't care how important the app's developers think their app is. It's my computer, it's my decision how "important" something is.
I don't care how important the app's developers think their app is. It's my computer, it's my decision how "important" something is.