First of all i just want to say, new member here. In fact, I just became a member to reply to this thread, although I have loved pro tennis for years(played in USTA, high school, and college myself). Admittedly, Monica Seles is my favorite player of all time. I am fairly young (25) and started following pro tennis in 2000 and Monica Seles was always my favorite for reasons I can't explain, she just was. First pro tennis match i ever remember watching was between Arantxa and Monica in the fourth round of wimbledon in 2000.
I realize that you are writing this article from a Steffi perspective and my biggest complaint is how you skewed the matchups. From the time Monica beat Steffi the first time to the last matchup before the stabbing, she held a 4-3 advantage. I think you have a good point that their individual matchup wasn't so one-sided for Seles except for in big matches at Grand slams. From their 1990 French Open encounter till their 1993 Aus Open encounter, Seles was 3-1 in majors. Kind of surprising how not-often they actually played eachother given the status their rivalry is given.
I'll admit that personally I dont really like Graf. Reading back on what happened, I don't think Graf dealt with the incident that well, but as you have pointed out, she was quite young too so I don't really hold that against her. I think she should've voted to reinstate Monica's ranking but she didn't. But, lots of other players didn't also (Sabatini was it right?).
However, perhaps unlike some other Seles fans I really don't like to do the hypothetical with her. Those grand slams she won in that short amount of time will always be hers. That speaks for itself. I feel bad for Steffi, cuz you know what? She played the 7 players that were most deserving each of those times that a Seles fan says she would've won those majors. Of course she had nothing to do with the stabbing and she only played the best tennis she knew how to in the years after it. Physically, Monica maybe could've been there, but mentally, she wasn't ready. That doesnt mean Steffi doesn't deserve her slams. But, tennis players are humans and things happen to everyone (I mean being stabbed during your job is a bit extreme, but still), so I'm not willing to discount Steffi.
Now, does it change my mind of her as the GOAT. Absolutely. I'm sorry, but lots of factors affect that. One of them might be your greatest rival being taken out of the game. So, no, I will probably never consider Steffi the GOAT. Right now for me thats Navratilova or Serena.