How much would you pay to play The Elder Scrolls using the whole Tamriel map?

Wont happen for a while.

Maybe they could introduce dragons and big creatures that you have to join up with guards/mercenaries to kill. They could have an ongoing system like when an area is clear of creatures lots go in another place and then spread back.

I would pay about £100

If they did it, I would like no main story quest. Think about it. In most RPGs, you get one gigantic quest...and a few mediocre side quests (with the occasional good one). Imagine an open game world where there were absolutely no limits on what you could and could not do, or where you could or could not go. Every NPC would have a quest for you. You create the world you want to create; you're not bound by limits in the questing system or NPC routines.

Also, the game world would react to your adventures. If you, say, kill the king and claim the throne, the court would look to you for guidance. The citizens would come to you for aid and advice. You could decide to annex another territory, or banish someone outright. You would have complete control over Tamriel.

What I mean is that once started, you do what you want to do, period. There would be no central quest/theme tying the game together: you would be on your own, creating alliances and friends and enemies your own way. Most RPGs have a main theme or storyline, even The Elder Scrolls. In my version, the only story lines would be the ones you create while playing.

EDIT:

To the OP: Yeah, I guess that's one way of looking at it. What I really am trying to say is that I wish there were more "good" quests in RPGs. You really only get one big one and a handful of minor "ok" ones. But my version would not have a clear end to it - it ends when you say it does, not when a quest is complete. In fact, it'd be more like a real-life simulator than a game. It would be hard to pull off, but I would like to play something like that.

nothing

im waiting for bethesda to recreate daggerfall with the oblivion engine

the game world in thatgame is twice the size of the uk