After watching a little more, I must retract the "slavishly" bit.
Looking at the novel right now, I am thankful that they left out a whole bunch of stuff... like Tripitaka's backstory. That would have made the pacing even more unbearable. Backstory is fine in the novel but too much of it on tv can be a killer. Also the Tang emperor's trip to the underworld seems to be at variance with the novel also.
In the novel. Tripitaka seems less concerned about his disciples killing other life forms. Here, he's a complete Nervous Nelly about anything being killed.