I've been doing the Japanese course ever since it was released, and I've absolutely loved it. However, with 40 skills and about 180 lessons, the tree feels a bit short. Will additional content be added to the course in the future?
I was looking at that today too. Compared to Spanish (317 lessons--last count I'm aware of), it is a very short course. Spanish for English speakers has received several content updates since I arrived in 2013. So, hopefully we will see content updates for JA for EN over time as well. :)