This article from law.com suggests: "For the ABA's effort to overcome the allegations of bias in its ratings, the Miers assessment may be a lose-lose situation. If Miers is rated well qualified, the bar group will be derided by those conservative stalwarts, such as columnist George F. Will, who have declared her unqualified and an embarrassment. If she is rated not qualified or less-than-unanimously qualified, the wrath will come from the White House, which disassociated itself four years ago from the prescreening relationship with the ABA that had been in place for decades."
It goes on to suggest the possibility of another form of cronyism, quoting one source who said: "Miers has had a lot of involvement in the ABA and there may be feelings of loyalty." Another source said that if Miers gets the same rating as constitutional law practitioners John Roberts and Ruth Bader Ginsburg, then the ratings don't mean much: "For the ABA to give [Harriet Miers] a 'well qualified' rating would really dilute the effectiveness of these ratings, not just to conservatives but to moderates as well."