I’ll get more into this when I get to “The Last Round-Up,” most likely, but my least favorite fanon character is Derpy Hooves. I don’t like the exploitative, mawkish nature of the way she’s used (the Save Derpy YouTube video is the worst offender), the ableist assumptions that went into her genesis, the slur in her name… she represents a side of bronies I’m always troubled to encounter.
That said, I’ve seen two interpretations of her I really like. The first is in the Lunaverse, where she’s always and only Ditzy Doo (which is marginally better as far as naming people after ableist slurs is concerned), the Element of Kindness, a hardworking single mother who’s had a very rough life and is of perfectly normal intelligence, although her education is a little spotty due to aforementioned rough life.
The second is this comic. It’s a great interpretation, and I want to see more like this.