This was mentioned on the first page, but I really appreciate that you brought up and shared a screenshot of the zoo's Expeditions article so we know things word for word.
It's a pretty great plan in terms of additions. Tiger Trail and flamingos could use the renovation, pygmy hippos, nile crocodiles and hyenas are great additions to the already spectacular Africa section, more bears are always good.
I would totally agree that the Sea Lion Pool is very unattractive and that I was surprised by that myself. A new sea lion exhibit would be a great addition to the zoo.
I'm not as surprised by them holding off on this as I suspect work on the Tiger Trail renovation may involve new exhibits for the gibbons and/or otters currently housed there, which would open up their options for renovating the Tropics building much more without the potential loss of some popular species, and it would reduce the building's focus by removing one continent. If they could move out the African species as well (Blue monkey/Cape porcupine, hornbill) then they could refocus the building entirely on the South American species, which would make for a much more exciting project than an updated rainforest building by itself.
Interestingly, press reports from the Tropics building opening suggest that during that renovation work, it was designed with consideration to adding outdoor sections in the future, so I'm a little surprised this hasn't already been done. It would be great to give the Saki/screamer/capybara mix some outdoor access, or if there is room add some additional species outside.
The whole flamingo/elephant/tropics/aquarium section of the zoo feels particularly odd to me, with the elephant and flamingo exhibits feeling very out of the way and distant from the two buildings, and no real unifying theme. I think a South America theming would work pretty well given the aquarium has the toucan/tamarin/mangrove tank, Tropics has a likely future focus there, and the flamingos are Chilean, but I think it would take some additional work to tie the area together neatly.
Shame the elephant exhibit can't be 'stretched' closer to the Africa section, huh?
I don't think they will add a gorilla dayroom and indeed with the exception of the giraffe renovation, the Kansas City Zoo does not seem overall to be interested in adding indoor spaces for animals with outdoor viewing.
I think with the loss of red-crowned mangabey it wouldn't be a bad idea to expand the leopard habitat over the mangabey space, although they could also take the opportunity to move the Blue monkeys out from the Tropics building to the former mangabey enclosure as well, since they are also an African species, though they are more eastern.
I would still consider West Africa a pretty strong part of the zoo despite the leopard and antelope exhibits being somewhat smaller than they could be though.
