If they were willing to put the money into it, they could easily make a river-themed water recreation area there with modern-day new materials. You could use a darker lining for the pool and then the water would LOOK like river water (in lieu of the robins-egg blue color of regular pools). I don't think it'd be THAT hard for disney imagineers to come up with something, it's all about the money i think.
FW is in DIRE need of at LEAST one other pool. Am i looking at this map right, for this HUGE resort, there are ONLY TWO POOLS? There should be NO LESS than FOUR pools for this size of resort, themed or not. It'd be different if the beaches were usable, but they're not as far as swimming in them goes. Something is needed closer to the marina.