Ora Washington for the Hall Of Fame?
You are forgiven if you don't know her, because not many people do. In fact, I only learned about her recently myself.
Anyway, Ora Washington was known in the 1920's and 30's as "the black Helen Wills." She was by far the best player of colour of her time, but unfortunately because of strict segregation that was implemented by the USLTA (and other governing bodies) she could only compete in tournaments with draws consisting exclusively of players of colour, in which she was extremely dominant. It was her lifetime dream of one day to be able to play the great "real" Helen Wills, but politics of the day made that impossible.
It's said by unbiased people who saw Washington play at the time that Washington was indeed talented, but that she was nowhere near on Helen Will's or Suzanne Lenglen's level. Having said that, the fact that she never got the opportunity to compete with the best makes it impossible to speculate on how good she would have been if she were given the same opportunities to mix it up with the best because you can only get better yourself from competing with those that are better than you.
I would argue that she should be inducted into the HOF. Not because we know for sure that she was good enough to qualify (there's a big chance that she wasn't IMO), but because they stole from her the opportunity to prove that she was.