The one sentence worked for me. All told I imagined a story where the apes were being subjugated either much worse than they ever were before, or for the first time, and it was that horror story that induced them to look on Caesar with betrayal. Further, I feel there might be an element of subjective point of view -- illustrating how Caesar's fears had come true. Structurally, it allowed for the classic valley before the peak, when Caesar took the lashings for the orangutan and inspired his apes once again to follow him.
Most of Caesar's actions and achievements were borne not of his own volition. He didn't intend to rally an uprising, he only wanted to protect his peoples. He didn't want them to get caught, yet he feels utterly guilty that they did. Which brings me to the Nova sequence, which I completely bought. Yes, while I was watching the maudlin sequence -- it didn't occur to me that once again Caesar would unwittingly be central to felling his enemy at the same time. I love how the narrative worked itself out in surprising ways. I was expecting an ape-to-man hand fight, but instead it was more poetic.
Due in large part to the CGI artistry. How Caesar's expression told his story -- from thirsting for vengeance, to regaining his soul with Nova, to redeeming himself by sparing the Colonel. None of that was spoken aloud -- and fuck it's an ape doing the acting.
We've got CGI characters in leading roles, playing complex emotions and sight gags -- and not once do we ever question its fidelity. It's stunning how I readily accepted the ape characters as I would normal, regular actors. I felt the story integrated well with the visual storytelling.