Ya, the whole Flawless Blocking thing just isn't a mechanic that the majority of people are going to use. I guess it's fine if you're a person with super reaction time, but for normal players, it's something that will randomly happen by accident on occasion, but by the time you notice the message, the input window to put in a counter because of it will already have passed.
That's not really an issue, since it's an advanced mechanic and better players will be able to use more advanced mechanics than average players. However, when it's part of a progressive reward system in a tutorial, it's just dumb to have it there.