I had heard from somewhere they were aggressively shooting for "one new attraction per year per park", unless that was wrong?
I'm crossing my fingers for an aggressive timeline:
2019: USF Bourne Show and IOA Potter Coaster
2020: USF ??? and IOA Jurassic Park Thrill Coaster
2021: USF Pokemon and IOA Zelda
2022: new park
Edit: could have Sing On Tour for USF in 2020. This attraction is currently slated for Japan in Spring 2019 (to replace Horror Makeup Show).