I have mixed feelings about this. One the one hand, it's sad to see fans finally thrown such a bone only for it to be recanted and possibly never surface again. And seeing relations between creators and fans sour like this.
On the other hand, the "derp" meme, not Derpy Hooves in particular, but the entire "derp" meme is kinda creepy and does seem oddly like exploitation and mockery of the mentally disabled. When I was in school, loads of kids said things like "hurrdurr I'm a retard" as a mocking, subhumanizing gesture. And come on, even if it's from South Park as something to mean "mistake", you know that's where the "herp derp" meme comes from.
It's fine for people to be fans of "Derpy" Hooves, but does her name REALLY have to be "Derpy"? It's a line from South Park. Can't My Little Pony be more original and less meta than that? And who is to say the South Park creators aren't being incredibly ableist themselves?
What's the worst thing is how this all ended out by suddenly rising to the surface now, now that the creators finally decided to canonize Derpy. It was an elephant in the room for many fans and non-fans alike that should have been addressed long, long before now.
To be honest, a lot of us felt that was wrong to begin with and it was why were preferred "Ditsy Doo". But we treated the "Derpy" meme as just "the internet being the internet and putting offensive things and references into everything. That's just how the internet is, it's offensive and inconsiderate and you have to pick your battles", and chose not to make an issue.
Also, why are people fans of Derpy? If you're a fan of Derpy, wouldn't you want her to be called the most respectable name possible, instead of one reminiscent of mocking disabled people? Because if you don't, doesn't that just make you look like you like the character because of a possible exploitation of the disabled for humor?
I love the character Derpy. Well, she's not super high on my list of favourite characters, but she's cute, nonetheless. And I support her getting more airtime and the like. But I've always been uncomfortable with the "derp" meme and I'm even more uncomfortable with it surfacing in My Little Pony. I have to put up with the disabled being mocked, dehumanized, and otherwise exploited on the internet as it is, I don't want to have to be reminded of that when watching My Little Pony.
But as much as I'm uncomfortable with the "Derp" meme, I'm much more uncomfortable with the people who have sent hate letters to Hasbro about this immaturely and are souring the relationship between fans and creators right now. Hasbro are only trying to do something nice and should not be bitten for it.
And please don't hate me for not liking the "derp" meme.