Hya Hurtlocker!
From what you say it seems like you've already gone through the basics and such; As far as possible projects for GSoC,
this would be a good point to look at. Kinda contains all types of ideas that people around here came up with. It should shed some light on the type of stuff that isn't implemented yet. When choosing a project, also take into account the number of people that might also take on the same one. Confident in your abilities? -> Go for anything
That's where community comes in. You should totally check out the IRC on #terasology, ask some questions around, see who's working on what and all that. If you have any questions, do not refrain from asking!