openmw.org

I am going to try to improve performance within both interior and exterior cells (in animation2 branch). With any luck slower machines will perform better. Not sure where to start right now though.

What are some areas/ideas I can focus on to speed up exteriors? I noticed that we are using 9 cells at a time, is this something morrowind does too? Would having less cells loaded improve fps; what would be the impact as far as features go?

Yes, MW does loads 9 cells too, though the viewing distance is lower. But if the slowdown is caused by the animation system, then performance improvement should be focussed on the animation system. I have the feeling that going for general optimisation techniques (like improved batching or adaptive viewing distance) would derail the development effort for now.
But actually, since the slowdown is only happening while the NPCs are animated (and we are not running any animation by default), I am somewhat okay with releasing a slow animation system for now.

For exteriors though, I am getting 30fps with no animation, I feel like we should optimize exteriors now.

Not convinced. There is still this mwrender slowdown to investigate, that we had reports about. Not sure if it really exists (haven't measured yet), but OpenMW feels slower now.
Any further performance improvements would be a major task, probably worth a release of its own (as the main feature). I think for the next few releases it is important that we work on things that are more directly visible to the user. We had awful little of these in the recent releases.