Control looks at a Spirit's ability to Push and Gather and otherwise move things around on the island, thus River Surges in Sunlight has a strong Control score.
Utility, if I recall, is more of a catch-all for things that don't fit into the other categories. Actions that grant energy or repeats of powers, for example, fit nicely in this category. I forget if any non-support actions also belong.
Allowing yourself or another spirit to place extra presence would probably count as utility too. And I actually wonder if removing blight wouldn't count as utility rather than defense. Cleaning up the mess that was already made isn't really defending to me.
Now I'm wondering how it was determined exactly how big each of those stat bars should be. Obviously they can be generally figured out e.g. this spirit is really good at defense, but doesn't produce much fear so fear should be low and defense should be high, but is there some formula for exactly how big to make them?
That could still mean it's subjective. 5 is a good number of levels for low, med-low, medium, med-high, and high. Maybe Eric or the play testers just came to a consensus.