You are doing a great job.
For what it is worth... I tried out the school version of Scritter hoping it would provide a way for me to work with my teacher to create decks of vocabulary to memorize. Turns out it doesn't really do any of that well and it has so many problems that It was useless for the purpose of teacher web based vocabulary lists. The school features of scritter are totally undeveloped and not useful.
You already have the base required of everything required to allow a student to dump in a vocab list and for cards to be self-created. If you one day though a web interface allowed some sort of student-teacher management of a vocabulary deck you would have something very good. You already have most of the hard stuff done.
Imagine how powerful this would be as a student-teacher tool if you tracked known words and could report student specific difficulties of texts (like http://www.wumaocorp.com/hskcheck/
) to allow teacher to personally manage students. It would be amazing. But now I'm just dreaming.
P.s. remember how much scritter sells the subscriptions for. Examine it as a business model some day.