Question:
"Is it all PvP in Cyrodil or is there more to it?"
Answer:
"(Its) literally the size of The Elder Scrolls: IV Oblvion...We have lots of things to do there besides PvP, but once you go in there you are in a PvP zone. So even if you're going through a dungeon or if you're trying to find some very rare crafting items, chances are you're going to see a player from an enemy alliance. And then its up to you two to figure out what to do from there."
http://www.youtube.com/watch?v=ydkXzJKXwjY
The developer pointing out something that should be obvious.
Are you worried that your friends will choose to play in another faction, thus preventing you from playing together? You can still dungeon dive and PvE in a world as large as TES: IV.
Are you upset about the lack of free-form/open world PvP? Do you wish you had to worry about enemy players while you were leveling or questing? Go play in Cyrodil.