Congratulations Fabrice on a very nice piece of work. I really like the concept of unifying sentences, vocab and kanji, and exploiting the links between them. Although it's pretty obvious when you think about it, there's nothing I know of out there that goes much beyond the basic flashcard idea. It's a terrible waste, but also a great opportunity for someone with your interests and programming/design skills.
For me, the main thing that's missing right now is the ability to drill in directions other than kanji to reading/meaning. For me, the most useful thing is to practice from meaning to reading. In particular, for sentences I want to practice expressing things in Japanese, using the correct particles and conjugations etc.. Going in the other direction is useful, but not sufficient. Maybe you already have this in mind, but this functionality is crucial I think.
The ability to grab vocab from edict is really great, and very nicely implemented. It's a huge time-saver and cuts down on errors. By standardising entries you automatically detect when the same vocab item appears in more than one list. You don't want to be accumulating multiple versions of essentially the same item just because of minor differences in the way it has been entered. The grammatical information in edict is also extremely helpful I think. If drilling a verb, for example, it's often important to see whether it's v1 or v5r, vi or vt. The edict part-of-speech codes are very compact, so maybe they can just be shown in full with the vocab item.
I wonder whether it's also worth having the ability to select out the different meanings identified in the edict entries. If you're drilling the meaning of まいる, (to come, to go, to die, to be annoyed, to be madly in love...), you could soon start wondering what counts as a successful review... Anyway, although edict has its faults, the benefits of standardising vocab entries across users outweigh the disadvantages I would think. Better to find ways around edict's limitations than drop the concept.
Another thing I would find useful would be the ability to view example sentences when reviewing vocabulary, especially when the nuance of the word is not obvious. This is straightforward to implement I would think; you just want the option to see those sentences in your collection (or other collections) from which you've extracted out the vocab item you're drilling. If those sentences are directly associated with the list you're drilling (e.g. associated with the same textbook chapter), they could be highlighted and appear first in the list.
Anyway, keep up the good work. There's potential here to produce a really unique and helpful tool for us Japanese learners, and hopefully something you can make a good living from eventually.
