I believe the best part of PvP is spontaneity. Never knowing when you will cross paths with other players will keep you on the edge of your seat for hours on end. A mundane PvE quest may suddenly become a real challenge when your group finds the enemy questing in the same area. Your favorite farming or gathering locale may be invaded by the opposition, causing you to team up and oust them so you can continue to ply your trade. Occasionally just traveling from point A to point B along the road has the potential to waylay you for the entire night as more players show up unexpectedly and engage with/against you (also mentioned today was fast-travel, which btw is also detrimental to spontaneous PvP). The system described in ESO seems to eliminate all the fun and exciting aspects of PvP and replaces them with a grind.
This post is not about ganking or griefing other players, there are fairly simple mechanics that can placed to prevent that kind of abuse of open-world PvP (WARs chicken is a good example, but ideally a system that simply levels-down a higher player to whatever zone they are in would be best).
What this post IS about revolves around getting people excited to PvP again. Get them out of the habit of grinding repetivive content like BGs for vendor/token-bought PvP rewards. Force players to venture out of the main cities where they can't just wait in queues or fast travel to their destination. In MMOs, the game world has basically been turned into a lobby, and that just isn't right. The game world should be filled with secrets, resources, mobs, and most importantly, players.
Being a big fan of both Elder Scrolls and of MMOs, it saddens me deeply to see that ESO will not have the top tier PvP I have been aching for. I'm certain I'll still enjoy the game for a month or more simply because it's Elder Scrolls, but without spontaneous seat of your pants PvP, I don't think it will keep my interest much beyond that.
While this post is simply one fan's humble opinion, my guild has just under 70 like-minded players in it. And I would wager that there are many more similar guilds made of similar players who have been unsatisfied with the stagnation of PvP in MMOs.
Thanks for reading, and I'm eager to hear what the rest of the community thinks about how ESO's PvP is going to stack up, for better or worse.
-B