Based on my visit this week, Islands needs:
Desperately more major attractions that aren't water-based. Dudley and River Adventure were useless at absorbing crowds for people who didn't want to get wet in 60 degree (or colder) weather. Without Toon Lagoon and the only major attraction in Jurassic Park, the park just doesn't have enough to do.
Another major attraction for Jurassic Park. I hadn't realized until this trip how small and empty the Island feels now - perhaps its the losing additional acreage to Kong in conjunction with the Potter loss, but man, it really has very little to do.
Another major attraction for Seuss Landing. This is the rare area that feels fleshed out, but the park needs more family, "safe" attractions that don't include constant dangers being thrown in our faces. Another *pleasant* dark ride ala ET or Cat in the Hat is needed.
A thorough rework or replacement of Poseidon's Fury and Sinbad. Poseidon was corny and unimpressive, Sinbad (which I had not seen in a decade and was forced to remember why) was straight up embarrassing. These are the only shows in the park and the only attractions for The Lost Continent - they need to be better.
A complete refurbishment or updating of Marvel, Toon Lagoon, Cat in the Hat and the River Adventure. Marvel and Toon simply have not aged very well - they pale compared to newer Universal environments like Hogsmeade. The queue videos for all 3 major Marvel attractions, while cool in script and storytelling, scream 90s animation and simply do not hold up or garner nostalgia. Popeye is usually in good shape, but Dudley has always been unfinished and not working properly and looks every bit of it. The greater area is more aesthetically pleasing than Marvel but is still filled with dozens of completely irrelevant characters (really only Rocky & Bullwinkle, Betty Boop, & Popeye have any lasting cultural resilience). There's no easy way to fix that, but it's going to continue to be a real problem.
The River Adventure was in dire straits. The animatronics have never looked worse. They were running the ride with the second Hadrosaur stuck in the upright position for the entire trip. Both raptors were broken and barely moving. Tiffany started her motions 10 seconds too late, as did the Ultrasaur. The ride was just awkward.
Cat in the Hat is just as bad. The taming of the profile caused some real issues in the black-lit "chaos" scenes and robbed much of the others of their excitement or purpose. The animatronics are in shambles, and many effects are MIA or apparently gone for good.
The park has a lot of great attractions when running at full speed, but right now the park is in rough shape. The current roster needs a lot of work and it needs to continue to expand for Islands to truly be a world class, full day park. Kong is a great start - a seriously really great one - but they shouldn't stop there.