From when I worked on Wild West Falls in the early 2010's, 99% of downtime was due to guest behaviour (i.e standing up on the turntable, or filming) when a ride stop would be initiated. Then when it came to restarting, the ride would chuck a tantrum and instead require a full evacuation.
However like every ride, it occasionally had its issues but overall it was very reliable when it was in its original state. The new boats, station etc have pretty much destroyed the ride for reliability and capacity as well and honestly I kind of wish they would have just put it out of its misery. However we know that any replacement we would have got would not be up to the standards that the ride originally had anyway.
In regards to the post about the pumps being shut off to do an evacuation, that was always the procedure. A ride stop normally could be reset and was used to stop the ride for a mechanical issue. Anything involving a risk of drowning (or water related) would be an emergency stop which automatically shuts off all the pumps.
An evacuation was not required for a ride stop as the ride can be restarted (normally). But if the E-stop was pushed, the pumps would drain and it would instantly become a full ride evacuation.