I would recommend introducing increased traits based on gender and class so there would be strengths/weaknesses based upon gender and class. For instance, a male rogue would be stronger than a female rogue of the same level, but the female may have more dexterity or stamina. I think it would be an extra way to use stats and give people more options on how to customize their toons.
And I've mentioned this before, but I think there should be class-specific questlines similar to Morrick so that if anyone rerolls or creates alts, it's not the same grind over and over again (unless they decide to replay the same class).
If they do this they will have to give players the choice of changing their sex/race, otherwise it would just be a slap in the face of people who chose say elves because they liked them over humans or dwarves. Giving a racial or gender ability at this point in the game would no doubt drive more people away.