The thing is... I love carnivores! But herbivores offer much more interesting and varied habitats due to being able to share space. Also, food costs for herbivores are much lower than food costs for carnivores. The end result is that I often have a zoo filled with herbivores and only a handful of carnivores due to their costs.
So this is a tough question!
I'll be perfectly honest and say that though it pains me, I would choose herbivores because I know I would use them more. That said, I do love me some carnivores, that can't be understated. So:
1. Gerenuk
2. Hirola (Hunter's Hartebeest)
3. Bontebok
4. Capybara
5. Three-toed sloth
6. Chamois
7. Wisent
8. Wild yak
9. Muntjac / przewalski's wild horse / saiga antelope
10. Golden mantled tree kangaroo
In short: some antelopes to round out savannah habitats.
The capybara and sloth for South American habitats, as they are quintessential South American animals.
Chamois and wisent for European habitats (don't expect them in a European DLC, as I think those slots will go to the ibex and red deer).
Golden mantled tree kangaroo for Australia.
Yak for Asian habitats, providing a Tibetan animal. The muntjac is kind of cheating, because it's actually a southeast Asian animal and we've just gotten a pack for that. So the muntjac could also be replaced with other Asian animals like the przewalski's wild horse or the saiga antelope. I expect the przewalski to be in an endangered animal pack of some sorts, and I suspect we won't get the saiga anywhere. So my vote would go to the saiga in this herbivore pack.