This take doesn't make a whole lot of sense to me. Other than yanking some throws now and then, which most shortstops do and which Cruz has gotten better on this year, some of the bigger bad plays in the field that he makes are on balls in the air.
There is no guarantee that he would acclimate to an outfield position, and even more importantly, the value tradeoff of having him at SS vs a corner OF spot would be tremendous and put a lot more pressure on his bat.
The sharpest defensive metrics have him about middle of the pack for shortstops or a bit worse. He's not going to get a ton better than that, but it's pretty par for the course for what you get from other elite power/speed type guys such as Elly and Tatis.
I can see from the eye test why there is this talk about Cruz, but nothing else about it makes sense. I'm not saying you are doing this specifically, but he doesn't get a ton of credit for the well above average plays that he makes with regularity. A case in point was the other night on a squibber ground ball from Altuve, which happened after the huge debacle in the field. He made a plus plus defensive play look completely mundane.
In his rookie year, he's not making that play at all, and especially not after a bad play just before that in the field. I don't mean to single you out in particular, as this kind of thing has been all the rage after Cruz had some bad games in Houston, but I think a little more patience is in order.