I'm slightly hesitant to change the enemy line of sight just because I want it to play like the original. I'd rather find a solution with my visibility issues, like giving them some kind of tint.
As for loading custom wads, that'd be really cool. The only problem is that DoomLoader isn't 100% complete, and I'm not sure how it'll react if it tries to load something in a map that it isn't expecting.
Doors are definitely an issue too. I'll probably add a mesh onto them to differentiate them from walls; a little triangle is a good idea.
Thanks for the feedback!