I love Sano but my epiphany on him came a few years ago, in a plate appearance against Chris Archer in fact.
All of us had already seen the same streaky Sano by that time, either locked in or zoned out. Sano was in one of his slumps, and Archer worked him to 1-2, then 2-2. Then I thought “yup, here comes the high outside fastball waste pitch, followed by slider low and away on 3-2, for swing and a miss,” and... that’s what happened.
I’ve only seen one game so far this season but I assume Sano still hasn’t changed much, otherwise this thread wouldn’t be here.
I think Sano is fine, there’s nothing really “wrong” with him, but he just doesn’t see the pitch out of the pitcher’s hand as well as the average MLB-er. So it takes Sano that extra moment to recognize the spin, get his body in motion, and by that time, it’s too late. So, knowing all of this, he makes up his mind to swing a tiny bit earlier than he should (also accounting for all the check swings we have seen over the years).
Anyway that’s just one idea.