I think it will be good for Wanita UMNO if there is a challenge for the top post as indicated by this malaysiakini article Shahrizat plans to take on Rafidah as any leader worth his or her salt must be prepared to face leadership challenges.
Otherwise Shahrizat will always be known as the leader who chickened out of party elections.
After all Rafidah has declared she will step down in June 2008. If the leadership is then passed to Sharizat ala UMNO, Sharizat really has not received her mandate from the members and will be susceptible to challenge.
Those who want to lead political parties are too squeamish to battle it out via their polls, they should avoid politics.