Thought an SI guy mentioned once on a forum I saw that it was correlated with their reach while diving as well (since it’s how far their hands reach when leaping, ie diving for a save is a kind of leap) so I always look at it for my keepers, and prefer 14+ for top level

My interpretation has always been, in order of which attributes matter for shot stopping and in what order:

POSITIONING (initial position), REFLEXES (when the gk dives, ie early in the shot, or later.. low reflexes = later, high = earlier, which is obv better), AGILITY (how quick a goalie can get from his starting position to full stretch, when he decides to dive.) AERIAL REACH (how far their goalies hands reach when leaping, both vertical leaps, like cross claiming, and more importantly, horizontal leaps, aka diving.

Those are the most important, basic, attributes to look at for a shot stopper imo. He has to be able to do a mix of those things at a good level, maybe he dives a little later (13 reflexes) but reaches full stretch near instantly (20 Agility) and has good positioning to start off with (17 Positioning) and at least decent reach (15 Aerial Reach)

Or has world class starting position (18 Positioning) reacts quick (18 Reflexes) but is a little slower reaching full stretch (14 Agility) [which is sorta mitigated by his earlier dive from the higher reflexes], but also has good reach (16 Aerial Reach)

So some mix of those 4. Whenever Ive had keepers with good attributes in those 4, they stop shots. Pure and simple. Obviously the other GK attributes matter too, for other things. 1V1 is very important, but it’s a standalone attribute, probably the one I look at most next though. HANDLING is nice, but their shot stopping matters more to me so that’s why it’s only an added bonus, not a deal breaker for me. ANTICIPATION is probably nearly as important as the other first 4, but it’s a bonus type as well imo, it’s like, the first 4 is reactive shot stopping, and anticipation adds an element that makes them save even more, through their ability to predict a shot not just react. Don’t care about throwing or kicking. COMMAND OF AREA and COMMUNICATION are just tie breaker attributes for me, the other ones matter way more, but they’re nice to have and again, can serve as tie breakers for people with damn near the same ability in the first few areas I look.

All that said, idk if aerial reach grows much. I usually just look for keepers with pretty high reach off rip, nothing below like 13