These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Too Cool To Stay Fused: Akidra is a Game Breaker that's so powerful (well not by Z standards, but nevertheless) that she had to have a restriction of the two involved in her fusion to not be on equal terms, a twist on the usual concept.
They Wasted A Perfectly Good Character: So Kazuto has half of the soul of an alien princess from a planet inspired by Norse mythology. But he's used as a Transformation Trinket instead. So much could have been made out of that plot point.