I always thought there should be at least one ranged thing, but I can't think of anything cool or original. Back when I bought my first VC army book (around 2000?), I thought some sort of corpse launching catapult would be cool with poison or demoralizing effects. Then TK came out with the screaming skull catapult and that idea was no longer unique. Now that skaven have the giant plague catapult thing, a rotting corpse catapult wouldn't be original either...
Personally, I have decided that ethereal units are the tradeoff for ranged, as it is annoying to have to direct spells or a magical weapons at a unit of spirit hosts when they could be used on something a bit scarier. Ethereal units fill the role to some extent as well, because they can float to the opposite end of the battlefield and kill warmachines and tie up smaller elite units that you might normally target with your ranged weapons.
As far as the taking over other races stuff goes, it probably would end up causing a bunch of whining from other people about VC being OP. As far as throwing in a bit of character into the army goes, I am going to borrow an idea from this forum and make spirit host bases with some dwarves, O and G, and undead painted ethereal like (because the GW spirit host bases are silly looking).
