I've been working on water rendering and mostly figured out how it works. It isn't yet screenshot worthy (and screenshots are terrible for conveying water effects) but I have made some definite progress already.
Thus far:
-I reduced the refraction displacement by half, which looks a lot better
-I reduced the reflection distortions by more than half, which also looks a lot better (although it still needs some tuning for distance effects)
--Currently I'm working on tuning the intensity of reflections and the fresnel factor used for intensity scaling.
To Do:
-Shore waves need more foam, and should produce foam trails when receding as well as when advancing.
Also: shore waves seem to be recalculating the shoreline every frame, which may be contributing to the expensiveness. The shoreline really should only need recalculating if the terrain is modified or if you change maps entirely (ie in atlas), and should additionally be cheap to cache. It seems like someone was aware of that at one time but it just never got done.