Now a little bit of my personal thoughts, having visited Dallas Zoo twice a year for the last half decade
Dallas Zoo already has one of the finest Africa sections in the nation, with almost every large animal from the continent: African elephant, giraffe, lion, cheetah, gorilla, and hippo. The one major species they are missing is rhino, which are comimg with this expansion.
Besides the major species the African side of the zoo will now have 2 large aviaries. The existing one houses smaller species which I would expect to continue. The new aviary will likely house larger species, which given the zoos past discussion of a new vulture exhibit in this expansion and focus on African vulture species, i'd imagine they will move the large group from Zoo North of Ruppell's Griffon Vulture.
Now the hoofstock species for this aviary will be interesting. Behind the scenes the zoo currently houses large groups of Somali Wild Ass, Bongo, Gerenuk, Speke's Gazelle, and Yellow-Backed Duiker. I don't know if any of these species will make an appearence, but given the zoo maintining large groups of them until at least late 2024 I would figure they have plans for some of them to go on exhibit.
One last comment would be that this exhibit would essentially complete the zoogeograhic layout of the zoo. Everything on the South Side of the tunnel is obviously African. Zoo North has long been a geographic hodgepodge but will the likely removal of the last remaining African species (Colobus Monkey, DeBrazza's Monkey, and Vulture) it will be split into four sections. The Herpetarium and Kid's Zoo will continue to lack geographic groupings, but the west side of the zoo will now be exclusivly South American (Maned Wolf, Andean Condor, Galapagos Tortoise...) and the North Side will be exclusivly Asian (Tiger, White-cheeked gibbon, asian cranes, small-clawed otter, clouded leopard). This will better enable future master plans after the completion of the current campaign. Overall it's great to see Dallas making progress on it's plans after largely being static as of recent and watching Zoo North hollowed out. With Fort Worth continuing there recent pace of additions, its good to see Dallas on the right track.