They need more colors and some different models its been the same ones for ever now.
They need to release new content that relate to corehounds before they can do that.
i mean some void core hound or shadow hound anything would be cool
More Corehounds would be cool. The Black Empire Assaults would’ve been a good chance to add some Voidy ones too. Though personally, I really hope they change Fetid Devourer to a beast so we can snag him next expansion. Cause that model, is amazing.
I agree I would love to have a model like that and it looks like there will be a unchained version in Shadowlands. They’re untamable at the moment in the Alpha, but things can change. This is what the light grey version looks like.
That looks cool, a bit different from Fetid though. However if those become tameable and Fetid doesn’t, well…it won’t be a complete loss. 
I think it would water down the semi unique model and make them boring.
But I must say, even though I don’t usually use my core hounds, they have such smooth running animations.
I’d like a blue Corehound, I have Chromehound but it doesn’t have that fiery glow.
It’d be nice if the Dark Iron Corehound was open for all races.
Maybe some more colors.
3 colors is enough for me.