DisneyDellsDude said:I believe that they were also going for the 'real effect'.
People that have supposedly seen the yeti have mainly just seen a glimpse of it. Just like ghosts, or the Lock Ness monster, the yeti could be real, or fake. They wanted you to leave the ride still thinking if you really saw the yeti, or was it your imagination?. This also makes you want to ride the ride again.
Any time a feature is disappointing and less than stellar, you can always count on a hardcore Disney fanatic to argue that it was intentionally done that way in the name of "great storytelling".