I've used several versions of the WS water, and never had an issue with it being too soft.
Note, for the Realistic Water product you want to store it flat. I used it on some 2'x4' boards, and stored them vertically. After a fully year, the water had flowed 1/4", making a bulge where the river left the board. So I flipped it over. Another Year later, and it was back to being flush.
The boards are used only in a game we play after Christmas, so honestly only view it yearly.
Other times I used it (ponds, wells, oasis, etc.) there's no issue. It was just being vertical for a year that did it.