I think it's being addressed - Rumours of a dark ride for the secret life of pets, in the toon lagoon area. Plus obviously Nintendo should offer some family based options. Always amazed me they've not done anything with the Grinch - that may hold people in that area of the park a bit better. I love Islands but if I'm not feeling like a water ride I skip through Seuss, to HP then all the way round to Marvel...so it very quickly becomes less than a half day park. Kong will help massively.
There was a rumour of Mt. Crumpit being built a few years ago - the decision was rumoured to be between Grinch and The Lorax - ultimately it seems as though they have gone for neither for now, but plans will probably exist somewhere.