I'm wary of affirmative action plans that aim to increase diversity, because diversity is concerned with the outcome, not the process.
Take a pool of 100 employees. Every single one of them is a white male.
If your goal is equal opportunity, you look at this pool and say, "the fact that there are no minorities or women is evidence of discrimination in hiring, therefore we must change the hiring practice so it does not discriminate."
If your goal is diversity, you look at the pool and say, "the fact that there are no minorities or women is a bad thing irrespective of whether it was a product of discrimination, therefore we must change hiring practices so that it results in more minorities and women, even if we have to discriminate against white men to do it."
I'm strongly against discrimination so I oppose the second line of reasoning, even if (and I have no trouble believing this) a diverse workplace is more productive.
That said, I have trouble taking a hard line against diversity, because people should feel comfortable striving to have any job out there, and diversity-oriented policies create an environment where people feel comfortable doing so. That environment is surely a worthy goal, and yet...I'm not sure it would be worth the tradeoff of discriminating on the basis of sex or race that it would take to create it. In a sense, using an outcome-oriented approach to force diversity is about making the process fair for future generations, but at a cost of treating current job/education-seekers unfairly. And that I understand but can't accept.