These two pics are so very clearly taken with elements yet to be installed and proper show lighting, plus the fact that you'll be slightly more elevated in the flume itself. I can't at all say that I'm "disappointed" in good conscience. The first pic actually looks like, provided the proper elements, could be neat. The second pic is almost nothing aside from the AA, but there are clearly things hidden in the dark there. Do we even have context of when these photos were taken?
BTW: I know it's Jim Hill, but he stated on the latest Disney Dish that the attraction may or may not open in June. The issues seem to be stemming from the hilarious (if true) fact that WDI didn't count on the boats moving too fast thru the attraction and at unpredictable speeds depending on the weight of the passengers the boat is carrying. So the show scenes are being passed too quickly to sell story elements properly. They're apparently working on the timing to make sure that all guests are able to hav relatively the same show.
Again, if that's true then that's some insane incompetence. It's not like this is an untested tech attraction, it's using the same flume that's existed there for nearly 30 years! How could this have not been a major issue seen early on... like when scoping out Maelstrom for feasibility!