Would you be able to interact with any part of the world besides the player? Would you have to stay within a certain distance of the player?
I'm not sure how the invade thing completely works aside from you fight each other.
That's really all it is. You try to kill the person you invaded and the person you invaded tries to kill you. Whoever wins gets a little reward from the loser. Whoever loses loses all of the experience they've racked up so far and gets sent back to the last checkpoint. (although they can get the experience back if they can get back to where they died without dying again).
Why do people... betray one another? They might as well... all just die instead. Welcome to my kingdom!
Nah, it wouldn't work for Elder Scrolls, although I do love the MP in the Souls series. Demon's Souls more-so that Dark Souls but I do love the Covenants in Dark Souls though, keep MP out of my Elder Scrolls, it's the only game I can sit down, relax and RP to my heart's content.
"Soul of the Mind key to life's ether, Soul of the lost withdrawn from it's vessel, Let strength be granted so the world might be mended..."