Usability: Add link to advance to next completed lesson's practice.
I think it would be a nice usability feature if when completing a specific lesson practice that you could easily visit the next topic from a convenient button or link. It should also keep you in the same practice mode, either timed or without a timer.
The advantage to the user would be I could review a topic in the style I want (lets say timed), complete the task and then move on through topics easily as my heart desires.
Right now I typically: hit home, then viewing my skill tree scroll down, select the next topic, hit "practice skill", select the practice mode...
It'd also save a bunch of pointless clicks on your server too, so we both benefit. :-)