NadalAgassi, I personally would rank Austin over Hana based on what I know. She was tough as nails and was able to beat Martina and nearly run Chris out of the game. Should Hana have beaten Tracy more often than she did? I believe so given Hana's ability to take leads over her. But Tracy was so mentally tough. And when she was #1 I respected her as such.
However, I am convinced that had Tracy remained in the game she would've had to change a lot to stay in the top echalon with M and C. Physically, I don't know if she could've kept up with them. She might've been relegated to fighting Hana for third. With Steffi on the way Tracy would be in a tough position in terms of trying to get back to #1.