I'm a fan of the Kata/hira. The general aesthetic is pleasing, although I agree that it doesn't seem, to have any direct connection to the general theme (apart from the translation). It gives a nice medium between clean lineart iconography and actual letters. While several express a disinterest in the current enter-key design, I'd just like to throw in my two cents, and say; you should still keep similar ideas in mind - if you ask me.
That having been said, I'm absolutely in love with the colorscheme and general theme of this set! I must have it! I'm also taking several plant morphology courses at university, and this would be sure to make any fellow student jealous