"I think part of where I trip up is the 'why' of the reaction - I'm far better at analyzing others than myself."

You really are exceptionally good at getting into a character's head and making the reader see their emotions and motivations and how they shape the character's actions (you've certainly gotten me to look at the Fëanorions from a different angle). Maybe consider mentally stepping outside of yourself and looking at it as if you were writing yourself as a character reacting to the story? It won't necessarily help you in writing individual comments and reviews immediately, but the self-examination and increased self-awareness will help develop that ability to figure out the why of your reactions in future.

Pardon, still loopy here, so you're getting unfiltered stream of consciousness.