This gets me curious about a Japanese version. Due to the larger number of basic characters (46) Japanese smart phone input already uses flick-joystick like motions, with pretty amazing speed (for a smart phone). The 46 basic characters are input using 10 keys with 5 directions each: in (press), left, up, right, down. Does CharaChorder support a press as well, or just left/up/right/down?
For instance there is a “kana” mode that let’s you direct input each kana with one keystroke only, which is way faster than romaji input, but is ignored by 99% of the population because the ROI on learning it is extremely low as you’re still converting to kanji at the end. To your point, a ten-key style input on desktop would probably be slower than kana input.