Brainstorming: Hammer Plugins

[Hollow]

I agree with Ich666 with 3dsMax or Maya... simple exporting plugin for props, prop type, skins, ahh that would be the wet dream of any mapper/modder

It's been done, for max at least:
http://wallworm.com/projects/utilities/docs/

[Shrinker]

I have thought about meaningful extensions to the simple navigation around in 3D architecture (the "camera") and decided that it shall be possible to tilt the view sideways, and also to set a new point of reference for the direction (e.g. make the ceiling or the wall the new floor, just for the camera).