I am not sure about this.
From the limited amount of sims I have seen today, I would say vision will help you pick up blitzers a lot. This has always been true but it is actually working this season without having to over do it I think.
So here is how I see it. I could be wrong.
Vision and speed will improve your pass blocking bar. Vision will help you pick up blitzers in the run and passing game. Speed and agility will get you there on time.
Confidence seems to do two things. First it keeps your moral at a good level all game. This is generally accomplished by the first softcap. Second it is a factor in common rolls in GLB. I bet it is part of the pancake reverse pancake roll.
I guess the question is which is more important to you. I would probably aim for 61 in vision, speed and confidence if possible. My choice would actually be based on training combos.