Plain and simple. She isn't important, because she is a BACKGROUND character. She is at best a "Where's Waldo" character that can be EASILY replaced by any other character. Removing her doesn't hurt the show in the slightest (due to her not having any importance). The show will go on just fine without her and it will never be about her.
Above all else she is offensive. Why? If you look at any other character in animation history that have her "qualities" they all have NORMAL names that don't have a history that can be traced back to the INTERNET or weren't created by people who create ADULT SHOWS/movies/plays (South Park, Book of Mormon, Baseketball, and Team America: World Police)
As quoted by wiki, "Derpy or Ditzy Doo is a light bluish-gray Pegasus who was given the name Derpy Hooves by the show's internet following due to her having a cross-eyed "derpy" expression in the first episode." Discriminating against Derpy would be the same as discriminating against an individual with a cross eyed problem or a physically disabled person or animal. This is an atrocity and completely unacceptable!
Being someone who likes MLP, I don't understand why Derpy has caused such drama. First of all, there have been characters that act like they are mental retarded before and they got away scott free. And there isn't wrong with a person being mentally slow so why should we ban a character like that? Shouldn't we be trying to promote characters like hat to teach kids that everyone is different?
I think she has a good character, and it should be stated. I also think that just because she has a disability does NOT mean she needs to be taken out!! People who dont like her because she has a disability are judgemental and stupid. 'But shes so offensive! Im SOOO Offended when I see her! She has weird eyes! She doesnt have a right to be on this show! " Who cares? Oh yea. NOBODY! Youre offended? Take a hike and find a place to put your butt in some cold water if youre that butt hurt.
She could set a good example, saying that people can be different and she could be a great figure for people for autism or so, sure she could be clumsy, but being nice and overall friendly can shape a society. If they just take her off, it's like a martyr: Lots of fans love her for who she is, taking her out is like taking a family member away from an innocent child.
I personally think Derpy is one of the funniest, cutest ponies there is. And it's not just about her. Not a lot of the background ponies ever get any credit or screen time in the show, but I guess you can argue with that one. Point is, I actually like to arrange my favorite characters in order of cuteness, and Derpy is like in fourth place, next to Twilight, Fluttershy, and Pinkie Pie. Thank you.
Derpy is and has been an interesting part of My Little Pony: Frienship is Magic since it's first days of popularity. She has been a source of fan adoration and love since the beginning even though he only said two or three words in total. She is basically good not only for business but for the show as a whole because she brings out a smile in viewers.