This was true for a while, but Derpy quit showing up after while. You know, with the whole derpygate thing and Hasbro kinda telling them that she can't be so out in front. They left her out of most S3 episodes. In fact, she finally showed back up in the finale today after a fairly lengthy absence. And she was super-hidden, too.
At least the Doctor still shows up now and again.
true. I see doctor more than derpy. but just a little bit ago, I watched "hearts and hooves day" and at one point during the song the fillies sing, you see doctor and derpy together on a bridge. all I could think was, "doctor and derpy together on a bridge on hearts and hooves day. OH MY GLOB"