Let's use the Zoos Victoria criteria list on these species:
Recovery: Addax and Oryx only
Ark: Addax and Oryx only
Ambassador: No - well not for any campaign ZV is using at the moment
Enabling: No
Research: No
To my mind this is the reason why Zoos Victoria (and others) don't want to import more different species of antelope (or deer or bovine).
Now for "Grant's Unpopular Opinion #482":
If you want a zoo with 75,000 different species of ungulate, then go to Altina - but this is not what I want from a zoo. I simply find this boring:
In my opinion when displaying ungulates less in more! For example, I think Mogo Zoo has it perfect - they have:
White Rhino
Giraffe
Zebra
Camel
European Fallow Deer
Four high profile "important" ungulates and ONE smaller one - the difference is that they have a huge herd of the fallow deer (not just 4 or 5). To my mind, this is how deer and antelope look best - in large herds.
WORZ (and Monarto, and Dubbo) have a huge herd of Eland. Individually, I have no interest in eland whatsoever, but when they are in a huge herd they look great - especially when sharing a large exhibit with the "important" species such as giraffes and zebras. The same can be said about the large herd of oryx at WORZ - it works because there are a lot of them.
It seems to me that this is what WORZ (and others) are trying to do with the nyala. And I think this is a great way to do it. They are a beautiful looking creature, but they are not the star attraction and never will be - they are a great supporting act.
The main issue here (in my view) is that no matter how people dress it up, antelope, deer or wild bovines are never going to tick the "Enabling" box - and most of the general public simply can't get attached to them or have the same feelings for them that they have for ungulates such as giraffes, rhinos, zebras, hippos or (maybe) okapi. They are always going to play second fiddle to the high profile, "exotic" ungulates I've just listed. I've even heard comments from the public about how they would like to eat them!
I don't want to come across as too negative towards smaller ungulates, so I will offer a positive option as well: If MZ do decide to bring in Indian rhinos once the elephants leave, then a really good "house-mate" for them would be a large herd (20+) of Hog Deer! They would be an ideal point of difference, AND they co-exist with Indian rhino in Kaziranga National Park, India - the place with the largest concentration of Indian rhino in the world. You could even include Hoolock Gibbons (also found in Kaziranga NP) - but that's too far off topic for this post.
In a nutshell, with smaller ungulates, don't try to display too many - but display them in a smarter way.