I have to agree with the OP on this. I always thought, even when they first announced it's conception, that it should have been built next to SDC. A one/two punch so to speak. Across 76 in that vacant lot they use for parking now would have been an excellent spot.
It's not the kind of attraction that people arrive at by accident or by a spur of the moment decision, as in just driving down the strip and deciding to stop in, like they do with so many of the other things on the strip. Going to WW is a planned adventure, they must be prepared with swimsuits, lotion, etc. So, they would have been willing drive to wherever it was when deciding to go there.
But.... TPTB decided differently, so there you are. I would guess that Branson city leaders at the time probably lobbied pretty hard for it to be located where it is.