Agree with you
@Zoofan15 about the region needing another Gorilla holder. If Adelaide really has decided not to go with being open anymore to being one perhaps Monarto might be considered (or Western Plains, Bongo would no longer be the tropical African anomale now that African Forest Buffaloes have all passed away).
Personally think the continuation of Giraffes at Adelaide makes a lot of sense (the area around the Elephant temple is not much more than 1,400 sq m of exhibit space (a bit more if space in the concreted off-display loading site behind was utilised too) so small in terms of a Giraffe and accompanying African ungulate or Ostrich paddock(s) even though would triple the size of the zoo's old current Giraffe paddock. Personally think maybe a small bachelor group of Gorillas would be the best for the site (although I know its a small area, but its a similar size to the main area of Taronga's Chimp' troop, perhaps if was three Gorillas maximum (maybe four) it would be an approvable living space for them).
My runaway pie-in-the-sky mind goes to the notion instead of using it as a space for two exhibits for Sri Lankan Leopards (could say that then Adelaide might perhaps have too much space devoted to big cat species and being light on ungulates or primates in the future).
That would mean the now abandoned habitat concept for them would still go ahead as additional living space for their expanded area for their Sumatran Tigers that ZSA seems passionate about wanting to show their commitment too further.
The other thought was perhaps Brazilian Tapirs in the future, or a planted rainforest space with (new import additions) Mandrills and (pie-in the sky bit again but not entirely ''out of the question'') Okapi and Bongo shared space (but again spatial needs would be greatly pushed to the limit/perhaps even unacceptable).
A what-if thought in the short-term while Adelaide is going through its transition phase before the future works start is while Amani and Mujambi's former home will be another Sumatran Tiger exhibit (both short-term and the site itself as part of their area come renovations). The adjoining 364 sq m fenced and roof covered trio of long enclosures recently used as holding areas for Mujambi etc at times (formerly Persian Leopards til 2010 and Jaguars too prior to that) could be used as a short-term home for a Sri Lankan Leopard if the internal barrier fences were taken down or access points cut into them for full use of all three cages. Even if just as a short term resident of the zoo for a few years if any of the Sri Lankan Leopards in the region were able to be potential residents there (or a further import planned to go to another zoo as part of the Sri Lankan Leopard program in the country, via Adelaide for 2 or 3 years), although do realise again 364 sq m is not the biggest of spaces, the exhibit is tall and can have a lot of climbing opportunity set up in the form of wooden poles and transplanted medium height trees. Just an idea, farfetched perhaps but Adelaide is now in a transition era over the next few years and with it sounding like Lions are not to be until their new very large exhibit is completed in a few years then perhaps a Sri Lankan Leopard would be a viable temporary addition to the zoo that means there is another big cat to be met at the zoo in next few years apart from their awesome Sumatran Tiger family and Serval(s). Would not be a first for Adelaide (their short term female Gorilla residents 2007-2008, and similar to Taronga with Indian Rhinos and Cheetahs, Perth's Chimp trio from Taronga 1998-1999 and Chester the white Tiger over the '95-'96 summer (also courtesy of Taronga), and Melbourne, Auckland and Taronga again with Giant Pandas in '88).
ps - thats fascinating about Asian Lions social groupings in the wild, had no idea. Would be good if there was a chance for our region to once again have two to four zoos at the very least interested in holding them, structured co-operatively around their natural female and cubs grouping and solitary or bachelor duo of males grouping (starting to understand a bit better why the unfortunate death in late 1993 of the Asian Lioness at Taronga by male Kutch happened if their social structuring is very different to their African conspecifics, although perhaps have missed the list of fatalities by male African Lions on African Lionesses in captivity, though assume its normally not an occurrence given they are the social grouped anomale of the wild cats).