I've heard this a lot with Mack PowerSplash being put forward too, but I really don't agree. I've been on a PowerSplash and while I wouldn't describe it as intense, it's definitely a thrill ride. They're big, fast, and intimidating to look at for younger riders.
What Dreamworld lost with TRRR and RHLR is two great family water rides. Those were the two really brilliant rides that every family went on together, from the adults down to the kids. I don't think they have a ride like that currently, and I'd even say Jungle Rush might be a bit too much on the family-thrill end for families with smaller kids to do together. The closest I'd say they have currently to a "whole family ride" is Sky Voyager, but even that doesn't quite fit the bill.
For me, yes, they need a new water ride, but it needs to refill that family ride gap. There are so many better thrill coasters they could build than a PowerSplash or Intamin Shuttle Water Coaster, they don't need the water ride excuse for that if they want a new big coaster. They need a flume or a shoot-the-chute, preferably well-themed, to be the new ride that every family flocks to together on a hot summer's day.