Regarding Flame Princess' character, it improved, or is it because we just exploited mais of it. There was the resemblance she had with children, how she wanted things her way and her behavior towards getting to do what she wanted. Her smarts were shown as well. There was this time that gave me impressions that she must be doing her own improvements to herself, such as the time when she told Finn "Oh, I was just meditating." what may be the reason but trying to look for some peace. So, I can conclude Flame Princess is becoming an individual little por little.
The episode became boring when Finn was just there ordering Flame Princess and being patient and that made the dungeon crawl not a dungeon crawl at all. The mentor thing, it was boring. Then came the shining moment that Flame Princess showed us the epic powers she has and, yeah, I went with it, but I expected bad events occurring afterward. Yet, Flame Princess surprised me, because, really, when we get the image of kids getting their ways, it's complete havoc. Flame Princess proved our theory wrong por doing the exact opposite what we expected her to do, burn, instead she applied what Finn had taught her earlier, she didn't hurt anyone, she just used control. And the irony is that was what the episode defied, the fact that some people constantly smother us for our improvement, when they can learn to trust us that we have some sense to know the right from wrong.
And in the end, it is true,she can take care of herself.
