I don't think Apple will release a black iPad Mini five. Although, I would like to see the iPad mini continue and offer a new Color as you mentioned, but ultimately I think Apple is straying away from the mini with how the Plus model iPhone has also expanded.
I think the mini is a great tablet for portability and acting as a media device, but I see it heading in the way of the iPod, which the iPhone has Ultimately consumed.
And the more I use The haptic home button , the more I appreciate not having the old-style pushbutton from the previous iPhone models. I could see Apple changing this feature on future iPad models to the haptic home button.