The arrow does go green- theres just one problem- you can't make all of the grass flammable. To make it flammable, it has to be more 'solid,' if you know what I mean- like a building, so if all the grass was flammable the it could not be walked through. But it still looks cool though, if I can figure out a way to get it out to people people can use it on their own stuff, I just don't have time right now, lots of school work.
One thing I am trying right now which may not be possible is siege towers- or at least towers that fire arrows/naphtha over castle walls. They work fine (like other siege models, you can move them pre-battle) but when you order them to shoot at something you get a ctd. I wish they would work!
Oh, there's one other thing I haven't seen many people do, outside of a little bit in the METW mod. You can mod the tree models in the game to be much bigger, and get huge forests, where your vision is actually obstructed and that look fairly realistic. The pines look better than the oaks, though.
Laus Deo,
Justin