I really hope exploration isn't limited by what faction you're in.

Nope.
Reman dynasty ended with the 1st era. This games takes place, I think, about 500 years after that.

I think that we will be able to enter other realms while undertaking quests that take us there. But we would likely be in a special instance where we are not interacting with players from those realms, just NPCs. Any quests that send us into enemy realms will most likely equip us with what we need to move about relatively freely until we start actually doing what the quests have us do. At that point, we stir up an antbed...

I hope that the "faction" thing only turns to a blood bath in PVP areas and we are free to explore all tamril even if we were lets say an altmer without being destroyed by God guards, so I'm an altmer and I want to go to morrowind, I can do that but the guards will treat me like sh*t (here is to hoping ) and say stuff like "I'm watching you.....scum" and i can do quests but the general disposition of the natives should be low.

and if a dumner (another player) wants a piece of me we can go to an arena or have a duel and do it with honor

I personally don't mind being limited to the regions of whatever faction I choose. It helps create a sense of faction or realm pride in the game, and makes the PvP even better. Now I am not sure if it will be exactly like DAoC, as in, the whole region of the other faction is out of bounds to you, but who knows. I think it made more sense in DAoC because you had greater distances between realms. You had Albion (England/Wales/Scottland), Hibernia (Ireland), and Midgard (Norway, Sweden, Finland). Those were three very distinct regions, and helped create the "feel" of each realm. Albion was very anglo-saxon, Hibernia was very celtic and magical, and Midgard was all viking-esque. I suppose the different regions in Tamriel are pretty distinct too so they could go this route. I just see them doing something more along the lines of some parts of the different factions will be accessible to everyone, for quests and what not.

This would be cool

This. I mean depending on how they do the game, this could be played out easily. If they have the disposition system like in Morrowind, you could travel to another faction's province, but the people there would have a fair degree of hatred towards you. So it would be harder for a player from the Ebonheart Pact to do a mission in the Aldmeri Dominion just because the quest givers don't like your race. So basically....



This as well. Even within factions, an Argonian walking into Morrowind would have a harder time with the locals than another Dunmer or even a Nord would.

In aion you can go to the oposite faction (Which is cool), but don't expect the guards to treat you nice, nor the OP npcs.

Edit:
OMG, this is so off topic.