Peronally, I'd like to learn more of the hardcore grammatical stuff. Getting all those little sneaky words correct... "de", "en"... etc. Word order is another thing I'd like to learn... Seems that translating directly from English doesn't work!
However, I understand that those who are learning aren't all on the same page and may want to learn something else at the moment. So yaaarr... That's my part said and done.
You're doing an amazing job, GC.