I never place much faith in GK ratings no matter how many stars he has. From my earlier post about scripted games, you know when your GK will have a mare and inevitably you will lose is when your GK has a rating of below 6. Even with a win, a GK will rarely get above an 8 rating. On those rare occasions where a troll may occur, the GK will save everything and get a 9 or a 10 rating.
A 4* GK can (and usually does) perform as well as a 7*. So I never bother power training a GK. I might buy a scout every 3-4 seasons (with one on one stopper SA) but that’s it. In fact only my attacking players ever get fed Greens. GK and defenders are always Scouts.