I also like nonsane better, for those reasons and because I would predict that using unsane in conversations with persons considered to be so, is more likely to provoke Logical Rudeness and dismissal in the form of "it's pronounced 'insane', idiot", than nonsane is likely to.
Nonsane is a clearly-separate term. Unsane pattern-matches to Ralph Wiggum.
Edit :Excellent suggestions in the comments. Two of them stood out for me:
We often use "insane" to describe people whose behaviour or beliefs are below the sanity waterline. But as most must would agree here, you cannot call someone insane with a straight face just because he happens to believe in magic.
I'm currently watching Future by Design, a documentary featuring Jacque Fresco and the Venus Project. Jacque came up with this word, "unsane", to describe people who basically, aren't rational because they haven't been exposed to the right ideas yet. Which would be different from "insane", which is more about irrevocably irrational people.
I like this word, because there isn't the tone of accusation we find in "insane". This neutrality makes it easier to say that we can do something about it. Insanity should be eradicated like vermin. Unsanty on the other hand can be fixed.
So, do you think this word, "Unsanity" might be worth using?