As I said somewhere else here, Modding the DD engine is extremely hard to do, It needs very good knowledge of it's scripting language, You'll have to pre-render all new chars/monsters/items etc you make using expesnive 3D software and soon and so on.
3D, as Far easier to mod, 1 set of rules for all 3D such as the gravity etc, animations could be coded in far any 3D model, so you only have to model and skin, add sounds and you've a fully functional model, with some animation work you'll have a new monster.
