I can imagine they'll invest smart with this one.
A coaster with inversions seems to be a almost certainty and a modern flume, rapids, shoot the chute or water coaster seems to be a logical addition.
Any supporting rides I'd imagine would mostly be family based with the current hardware in the area being more family-thrill along with the major rides being a coaster and potentially a flume.
A Mack Seastorm, Mack Teacups or Mack Twist N Splash would be logical fits for the area. I'm thinking the Seastorm is a logical replacement for the Dragon like how Windmill Towers replaced the Jumping Bean/Jack.
Other options include a Gerstlauer Polyp, Zamperla Nebulaz, Dodgems, a Mini Jet style ride or a larger Pirate Ship ride. Although I don't see all of them coming initially.
If anything thrilling will come, I'd see it being a single ride (or two if we're lucky) to complement the existing offering such as a Zamperla Endeavour, Zamperla Hawk or a Zamperla Air Race. A supporting thrill ride to add to the thrilling signature coaster I'd say.
We do have Edge, Cobra and Magma included to be rethemed already so it's possible we won't have too much family thrill, it'll be either family/children's or it'll go to the other extreme and be more thrilling.
I can imagine any rides that will come will both replace Raging River and Dragon with upgraded replacements along with adding rides that the park haven't already got in their offering.