You complain when they don't give women anything to do, you complain when they do. Just because Uhura was unsuccessful negotiating with Klingons doesn't mean she sucks at her job.
It reminds me of when Damon Lindelof said that they had talked about an early idea where Uhura has to negotiate with a Klingon fleet that's heading to Earth while Spock is fighting Khan. And some fans got very angry about how such an important job is given to Uhura. I'm sure many of them were the same ones who go on about how "She's just defined by her relationship with Spock."