Many of the schools' school techniques have some lore/fluff in them; several don't. Hopefully, that's an oversight, because if not, it's going to leave some impressions of blandness for those schools.

Example Good: Bayushi Manipulator School. The ability has a thematic fluff paragraph, and a mechanics paragraph.

Example Bad: Ikoma Bard School. The school ability is pure mechanics text.

These relatively minor lore elements are very helpful to players, especially those new to the setting; they are helpful by providing the when and why to use the ability.

^He speaks truth here, it may seem like a bit of fluff, but it frequently helps newer players understand what the technique does in narrative terms.

More than likely just an oversight - I can't imagine them not having at least a paragraph for each school.

Also, you have to remember, this is still in the Beta Tests. They're out to test the system with Beta, and adding what fluff they already had done. By the time it's actually out in a full form, i'd be willing to bet that they'll all have fluff and any Beta Inconsistencies/Problems will be worked out... or at least the consistencies not intended as Side A believes this and Side B believes that... creating numerous issues that causes future war X to break out.