Just a thought for now but I post it while it's in my head.
Gavan did a really great job developing his engine and the result is really impressing.
However with the new perspective camera + possible support for CastAR and Oculus Rift there is a huge need for top performances.
I think Gavan already has an mental roadmap for that but he can't possibly be expert in all computer-science fields (plus he will be quite busy with AI and gameplay).
That's the motivation behind this thread: a place for Gavan to expose his 'problems' and a place for experts from various domains to answer and propose optimizations.