There is a heightmap generator already.
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=518432#Post518432 (I've added a link to this on the wiki now).
You can "randomly" place items using the "Instance Painter".
Roads are annoying to draw with a mouse, I'll grant you.
Rivers are kinda weird, but they aren't a huge amount of time to spend compared to everything else (like the pile of shit roof editor).
I'm not saying that more (and better) tools wouldn't be appreciated, but at the moment we are still struggling with basic bootstrapping (scripts, resources, etc).
