I for one, have always felt like the ghosts in TES aren't very....erm, ghostly. The main reason for this being that they're fully visible. I think that they should pose much more of a challenge, I don't want them to be OP or anything but I feel like at least a Detect Life effect should be required to see more of them than a faded and barely noticeable face. They should also appear a bit more human in form, the ghosts from OB looked more like some monkey with a permanent invisibility spell who got the upper half of his body covered in flour. Also, I feel like some ghosts should merely be there for a scare factor. Say you walk into a house with no apparent owner in the wilderness and decide to stick around for awhile, eventually, you would start hearing faint voices, then something in the background might start hovering around a bit, and if you don't leave after awhile the spirit would become violent, throwing things at you, screaming, and eventually making itself somewhat more visible to begin combat. A ghost of that sort should be much more powerful than your typical one, and at low levels should be near impossible to defeat. Afterward, sense you likely weren't able to defeat it, you would flee and some local would speak to you about the house explaining its history and what not. This might start a quest and it might not.
But anyways, tell me your opinions on this.