Since the 4th generation of the series has equines playing arcade games, I figure why not come up with a controller that would be designed for a home console with them in mind.

Sphere holographic display of whatever game the equine decides to play.

A 360 directional pad around where the equine puts the front of his/her/hir/its muzzle.

A holographic select button that stays above the equine's left ear in such a way that it can intentional be used by the equine without being able to be accidentally pressed by the equine.

A holographic start button that stays above the equine's right ear in such a way that it can intentional be used by the equine without being able to be accidentally pressed by the equine.

A scanner spot at where each of the equine's 4 hooves should go to help to determine the size, weight, and strength of the equine using the controller.

8 buttons around each of the respective scanner spots that can move in and out to lower the risk of accidentally pressing them when the equine doesn't want to while increasing the chances of the buttons being pressed when the equine wants to.  Multiple of the buttons can be pressed at once.  And if the equine jumps straight up than up 32 buttons should get press at once.

A home button a little ways in front of 360 directional pad so that the equine will have to use his/her/hir/its tongue to push it while in a neutral position.

Plus a tracking device in the back for any additional command the other controls don't allow.  And it defaults to recognizing the equine tail while ignoring everything else.