I was at first thrilled to find that Swype supported Japanese input, but as several commenters pointed out, it is indeed the exact opposite of using a wnn (Japanese IME) keyboard as your primary input. Japanese keyboards are great for Japanese, but support for English is lackluster. If you need to enter more than about one word, it's usually faster to switch keyboards entirely. I have a friend who I thought were always drunk, until I realized he exclusively types English on the Google Japanese Keyboard.
I'd say that Swyping to type Japanese on the current version (1.5.14) of the Swype keyboard is a decent option for about 40% of what I type. I can manage to enter about 80-90% of words by typing them on the Swype keyboard. For the rest, you have to fallback to typing individual characters using either the on or kun readings, or typing common words that contain the desired kanji, then deleting the unneeded characters.
So after using the trial and purchasing the pro app (It's worth 99 cents), here are some suggestions for improvement, ordered by obviousness (to me):
(Let us know your suggestions and we'll add them to this list.)
2. Better swype prediction. If hunting and pecking around the keyboard brings up the correct word, then the same should work when swyping across the keyboard, except that it doesn't. Any sort of semi-complex verb conjugation will fail. Try swyping 犬に噛まれた (inu ni kamareta; bitten by a dog). It's not possible.
|The order of swipes clearly resolves to kamareta, which is not an option.|
Swype fails to understand the conjugation and suggests a word that isn't even close (misses the ma for a ka. If you peck this out on the keyboard, you can enter it with no problem. This behavior is consistent; Swype fails so poorly to understand the conjugation, it suggests words that aren't even words (飲もいや？ WTF does that mean?), like in the below example.
|Total fail. Maybe I should type 飲みましょうか？|
3. Add a dedicated enter button. This is absolutely necessary when typing Japanese using an IME. You must have a way of accepting the input as entered, ignoring all the suggestions. See this example. type 俺 (ore; I), then も (mo; too/also). There is no way to do enter the mo as "also" instead of something dumb like "algae" because, unbelievably, the simple hiragana is not an option in ANY of the suggestions. Seriously. (You have to switch input methods to accept this as も and keep typing.)
4. Add swype support for kunrei-shiki romanization (once you fix number 2 above). I don't type Japanese by phonetically spelling words out using the Hepburn system (e.g., Tsuyoshi). It's faster to just type tuyosi. Typing on the Swype keyboard supports this. Swiping does not. "Tsu" requires you to swipe your finger all over the keyboard. "Tu" does not.
So that's call I an think of. Do you have any suggestions for improvement?