Direct X Support was removed I think some time after v0002 (unless it somehow made its way to retail beta)
It was outdated and worked poorly, if we had updated Direct X Support that could fix many things, maybe even the light
limit, or other graphical bugs.
As far as I know Direct X support was removed due to its poor performance, however I heard it is not removed, according to what I read about TGE the option is hidden from the game (I could be wrong about this).
If we can improve upon the way it functions it could lead to any number of possibilities, maybe even better performance where those who don't have good performance with OpenGL(I run 60fps on OpenGL, its not really an issue on my end)
I don't really know what else could be improved with fixed DX Support, as there may be drawbacks with it as well.
It could be possible that optimizing OpenGL could be a better option...
/Discuss