I would say KZ or MIB area, the reason being is that since they have that unused land by Men in Black, it is a better use of space to use that are that is being unused rather than take out 2 rides that do get a good fill in the summer. That would just make other ride lines longer and truly is bad for efficiency. Plus, since they are moving towards IOA optimization with JP and Kong, and some other things they will then revert back to Uni, UNLESS they take 1 year off from both to create the water park. But after Kong my Bet is Waterpark and going back to USO
I think Comcast is firing on all cylinders right now so until 2019/2020 - I don't think they're going to stop the construction.
Even after Kong and the JP expansion,
Toon Lagoon is looking to be rethemed/replaced in the near future.
Lost Continent desperately needs an anchor attraction to draw guests in (potential reworking of the solid amount of backstage space behind PF and Sinbad is likely).
Seuss still needs some depth in terms of family rides (not just flat rides) and they need to make the Seuss Trolley all-ages. A full-scale yearround show, a family (Big Thunder sized) coaster, and another all-ages dark ride would be PERFECT!
Marvel is a conundrum that Comcast will eventually want to deal with (Dr. Doom is a massive eyesore and the Hulk could use some upgrades) and may consider re-theming if Disney gives them enough reason
Even JP could use a fixing of Pternaodon Flyers and some TLC for the Discovery Center (which might be coming).
The jr. wooden coaster and flat ride in the Triceratops plot is the beginning of the lovefest on IOA. The park has only gotten one major addition in 15 years (granted, it was 2/3 complete after Flying Unicorn and Storm Force were added, then decreased once the Skipper Tours and TE were removed) so a few are likely in the last 5-7 yrs.
USF will probably take a break after Potter until the double-whammy of KidZone revamp and the MIB/Springfield plot project open.