The point on having a multi park resort is to not have the same things at each park. This park does not need any style water ride that another park in the resort already has, in my opinion.
As it has been said, the park has enough coasters as it is. The resort, as a whole, has a good variety of different coasters to satisfy almost every coaster fan.
Lastly, if they do add another land, I would hope it is not singular IP specific. I am giving Berk a pass as it is for kids and Potter is an exception as the world of potter is so vast and diverse. Even though it is potter, its essentially Paris which makes it not feel singular. Same with SNW. It is the Nintendo brand but different IPs that create the world like Darkmoor. So yeah, I hope they think long and hard about the next land expansion and make it worthwhile.
Now that I think about it, IOA was the perfect park that executed multi IP lands as all their islands featured several IPs under one umbrella with the exception of JP.