I'd love to be able to use HeliBoard to type Japanese. The basic idea I had in mind would be to use the suggestion bar as a way to convert typed romaji to hiragana/Kanji. Perhaps space bar could be used to switch to a different view to select the correct conversion.
I love HeliBoard for regular qwerty typing, but I just want to be able to switch between English (and other languages) and Japanese quickly without having to switch to an entirely different keyboard app.