Interestings topic. I think that heroes and sidekicks have some layers of power and politics to it. Sometimes it is gender, sometimes it is race, but in both movies and literature there are quite a few examples of secondary characters who are more talented or do more than the main character or hero.
Hermione, as you mention is probably the most remarkable case in modern pop ulture.
I like Gromit, from Wallace and Gromit the british animated cartoon. The smart dog does all the job, the stupid Wallace takes all the credit.