I never recall MJF smiling when playing - she never seemed to be enjoying being on the court. Her lack of emotions - maybe she was concentrating like early Evert - was a turnoff. Also, the grips she used seem to limit her game on both sides. A flat hitter - yes - but there was a lack of versatility and lack of a big shot. Hitting so flat limits how hard you can hit the ball and results in a game style that is more defensive than offensive. Flat hitting also results in a lower percentage game. MJF did not have a big serve either. To reach several slam finals you have to be a really good player and she was but did she really have a championship game? No.
I just never got the feeling that Fernandez ever felt a desperate 'I HAVE to win this point, this game, this match' intensity that baseliners a la Evert, Austin, Sanchez, Seles etc never really escaped from. They had to win every single possible point through tenacity and focus. To play that style, you have to be so driven,
so emotionally invested in just not losing todays match that the kinds of shortcomings you mention here are not permitted to penetrate. There is a total belief that a loss today, will lead to tomorrows, and the next days losses. Its a zealot's protection of an athlete's fragile ego, that Fernandez did not possess.