As the title says, beguile should be in all schools! I know what you are (probably) thinking; it would make death less unique. All other schools would have their own beguiles with more pips (~5). Just a simple idea.
Um, I don't think how well that could work out. With the maximum level soon increasing to 100, it would take a long time for the other schools to get their own Beguile. By that time, I'm not sure how appreciative the other schools may be. Anyways, there are treasure card versions of it available, if you really want to use it with other schools.
But Death would be a little left out... What could Death get instead? Would all the schools start receiving Guardian Spirit after that?