I was just thinking about this as Graf's 1988 season had one blemish, she didn't win the YEC.
In my books, a perfect season has the YEC title besides CYGS. To win CYGS, you once needed to win on four different surfaces; grass, clay, and two different surfaces. Well nowadays they play more or less the same. But anyway, one court type is missing, it's indoors. As indoors lack a slam, YEC is the closest to it, and that's why a perfect season is CYGS with YEC.
But there are the Olympics once in four years. Olympics is pbviously very important for the players. But being only once in four years, it just doesn't suit among other tennis achievements. CYGS with Olympic Gold can't be any more perfect than CYGS in a non-Olympic year. So, I really rate (CY)GS with YEC at least on level with (GY)GS with Olympic Gold. I'd otherwise rate (GY)GS with YEC ahead of (CY)GS with Olympic Gold but I rate them on level because of the importance of OG to players.
In my books, a perfect season has the YEC title besides CYGS. To win CYGS, you once needed to win on four different surfaces; grass, clay, and two different surfaces. Well nowadays they play more or less the same. But anyway, one court type is missing, it's indoors. As indoors lack a slam, YEC is the closest to it, and that's why a perfect season is CYGS with YEC.
But there are the Olympics once in four years. Olympics is pbviously very important for the players. But being only once in four years, it just doesn't suit among other tennis achievements. CYGS with Olympic Gold can't be any more perfect than CYGS in a non-Olympic year. So, I really rate (CY)GS with YEC at least on level with (GY)GS with Olympic Gold. I'd otherwise rate (GY)GS with YEC ahead of (CY)GS with Olympic Gold but I rate them on level because of the importance of OG to players.