Given that there's a ton of locals there with the same three or four slides on their minds, it makes sense that things are a bit lopsided right now. Once that crowd disperses things will flow a little more accordingly. I do like the option of giving people more than just the rivers/wave pool during the waiting period. An adult water fortress embedded into the volcano would have been a nice addition to remedying some of these issues.
Alas, this shows the importance of having high-capacity rides in parks like this. Given the hysteria, a Proslide Mammoth seems to be needed like yesterday.